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Gallery, Projects and General => Project Logs => Topic started by: kvom on August 11, 2009, 02:55:01 PM

Title: Another Halo
Post by: kvom on August 11, 2009, 02:55:01 PM: I was inspired by Bogstandard's starting to build this engine, and it looks as if it would be a good (or ambitious) step up from my first two engine builds. For those not familiar with this engine, it's a 5-cylinder radial: http://lineymachine.googlepages.com/l5 (http://lineymachine.googlepages.com/l5)

Since I still have a bit to finish on the paddleduck engine plus blinging it and Brian's beam engine, I will work on this in fits and starts as time allows. In the meantime, I still need to accumulate tooling that I don't already have.

The first bit is a very thin lathe grooving tool to cut the fins on all the cylinders. The plans are showing .025" grooves, which seems almost paper thin to me. I started by grinding the end of a 3/8" HSS blank on grinding wheel, till I had a width of around .07. The remainder of the forming was done on a manual surface grinder at school. The sides need relief, and I guessed at a 5-degree angle on each side (10 degrees included). To achieve this a sine vise was set at 5 degrees using gauge blocks, and the tool clamped in the vise with the botom side of the tool on the high side of the vise jaws. The left side of the tool must be ground first in order to support the tool with a parallel when grinding the other.

I actually ground it down to .03", but decided to stop as the bottom of the blade was so thin. I think that 5 degrees is too much; 2.5 should be better.

Here's the result:

(http://www.pbase.com/kvom/image/115971652/medium.jpg)

The grooves in the cylinders aren't critical dimensionally, and aren't deep. We'll see how the tool holds up.

Another necessity for this build is a rotary table, and some of the parts will require that it be mounted vertically. I'd been shopping for a rotab for some time, and found the PhaseII 8" H/V on sale at Enco. Unfortunately they don't honor the free shipping on these tables, and shipping would have raised the price by $75. I called MSC, which has a local presence, and was told that they'd match the Enco price. I picked it up yesterday.

Here's the packing crate, along with a piece of 2" thick 8" diameter aluminum that will be a mounting plate for a 3-jaw chuck eventually. Alongside is a D1-3 backplate that I will use to attach the aluminum to the lathe to cleam up the faces and edges.

(http://www.pbase.com/kvom/image/115971637/medium.jpg)

Inside the crate:

(http://www.pbase.com/kvom/image/115971641/medium.jpg)

Once out on the workbench, the only pre-install work to do is to fill it up with spindle oil and clean the table surfaces with mineral spirits to remove the residue from the packing paper. A thin coat of oil and it's ready to be mounted.

(http://www.pbase.com/kvom/image/115971644/medium.jpg)

Eventually I will try to separate the vise and rotab a bit, but I didn't want to take the time to retram the vise. There is no vertical slot for the right side. Instead it must be clamped with this supplied bolt/nut/clamp combo:

(http://www.pbase.com/kvom/image/115971647/medium.jpg)

There are two other similar clamps for mounting the table vertically.

Here's the first method I decided to try to center the table under the mill spindle. I chucked a conic piece of metal that I use as a bull center on the lathe, and positioned the table so that it fit snugly all around when lowered into the center hole. Then I measured with a DTI, which showed that I was less than .005 out of dead center; good enough for me!
Title: Re: Another Halo
Post by: Brass_Machine on August 11, 2009, 04:24:30 PM: Way to go Kirk. You are wacking these projects out! :nrocks:

Eric
Title: Re: Another Halo
Post by: CrewCab on August 11, 2009, 04:29:55 PM: Nice choice Kirk, (Engine and Rotab :thumbup: ) .............. you'll do fine, looking forward to the build.

CC
Title: Re: Another Halo
Post by: bogstandard on August 11, 2009, 04:31:04 PM: Kirk, I am half way thru the finning on the cylinders, but I am unable to finish them at this time.

I ground up half a dozen 0.025" wide by 5/16" long slotting tools, I ground them up 3 at a time. But I do ensure that my machine is set up exactly square on the topslide and toolpost, so I can get away with no side relief, as you are plunging in only a matter of 0.125" at the deepest point. Doing them with no side relief, they are not so fragile.

John
Title: Re: Another Halo
Post by: kvom on August 11, 2009, 06:18:50 PM: The rotab doesn't come with t-slot nuts, and the slots are smaller than the Bridgeport table. I measured the slots and did some internet searching. One eBay seller has the size that fits at a price of $22 for 10. I can't see needing 10, so I decided to make some. The width of the slots at table height indicate the need for 7/16" studs. I happen to have a foot or so of 7/16-14 threaded rod, so I went to the local hardware store to purchase the locking nuts. Once back home, I discovered that my tap&die set has a 7/16-20 NF tap but not the NC. Back to the store to purchase a tap. I then spent a good 90 minutes milling the necessary t-nut form in a 6" length of mystery steel, then cut off 4 1" pieces.

After dinner I need to drill and tap them. Hoping not to break the tap.
Title: Re: Another Halo
Post by: Bernd on August 11, 2009, 07:02:28 PM: Kirk,

I've got almost the same table, except mine doesn't stand horizontal. I discovered the same thing about the bolts and T-nuts. I improvised for now but need to make a good pair like your doing.

This is going to be a very interesting thread. Why? Because I think you did an excellent job on the Paddleduck engine and I'd also like to build a radial engine but steam power it and put it in a boat. Sort of like an air boat but with a steam driven engine.

Bernd
Title: Re: Another Halo
Post by: Brass_Machine on August 11, 2009, 07:55:41 PM: Quote from: Bernd on August 11, 2009, 07:02:28 PM
...I'd also like to build a radial engine but steam power it and put it in a boat. Sort of like an air boat but with a steam driven engine.

Bernd

Holy cr@p Bernd... we need to talk. I want to do this as well!

Eric
Title: Re: Another Halo
Post by: Bernd on August 11, 2009, 08:48:15 PM: Quote from: Brass_Machine on August 11, 2009, 07:55:41 PM
Quote from: Bernd on August 11, 2009, 07:02:28 PM
...I'd also like to build a radial engine but steam power it and put it in a boat. Sort of like an air boat but with a steam driven engine.

Bernd

Holy cr@p Bernd... we need to talk. I want to do this as well!

Eric

Ok buddy lets talk. Start a thread. I've got some ideas.

Bernd
Title: Re: Another Halo
Post by: kvom on August 11, 2009, 09:08:45 PM: Theoretically the Halo can run on steam as well as air. However, it doesn't have a reversing mechanism AFAIK.
Title: Re: Another Halo
Post by: kvom on August 14, 2009, 11:10:42 PM: After working on the Jeep all afternoon, I still had a little energy for some machining. I haven't decided which chuck to buy for the rotab, so I started to clea up the aluminum mounting plate. The first order of business was to center the lathe backing plate and drill four holes for the 3/8" mounting bolts:

(http://www.pbase.com/kvom/image/116095223/medium.jpg)

Note that since the disc is 8.25" in diameter, I couldn't clamp it normally in the vise. I reversed the hard jaws on the Kurt to allow clamping it for drilling. Once the holes were through, I pulled out this countersink that I'd gotten along with the mill in order for the bolts heads to be below the surface of the plate. Useful gadget. :thumbup:

(http://www.pbase.com/kvom/image/116095224/medium.jpg)

Now I could mount it at the lathe to clean up the face and sides.

(http://www.pbase.com/kvom/image/116095225/medium.jpg)

Then I flycut the reverse side, hopefully yielding a plate that will keep the enventual chuck square to the rotary table.

(http://www.pbase.com/kvom/image/116095226/medium.jpg)

The next step will be to cut 4 mounting notches into the side to attach it to the rotab.

(http://www.pbase.com/kvom/image/116095228/medium.jpg)

In the meantime, I will try to start on one part via the CNC lathe at school: the cam housing. The first screenshot show the simulation of the g-code for drilling and boringL

(http://www.pbase.com/kvom/image/116095230/medium.jpg)

Assuming that works properly, the piece is turned around in the vise to turn the front profile:

(http://www.pbase.com/kvom/image/116095231/medium.jpg)

I'll try them out on Monday afternoon.
Title: Re: Another Halo
Post by: kvom on August 15, 2009, 09:14:58 PM: Still tooling up. Today I ordered two lathe chucks. One, from a guy on PM, is a 8" 3-jaw chuck with D1-3 mount and 2-piece jaws. This will go on the lathe when I need soft jaws.

The other is a 6" plain back 3-jaw with 2-piece jaws that will go on the rotab using that Al disc as a backplate. Found it on eBay. Assuming TIR isn't too bad I should be able to center work on the rotab. Otherwise I can make some softjaws and center them that way.

Otherwise no shop time today as I was helping a friend swap a transmission into his Jeep all afternoon.
Title: Re: Another Halo
Post by: kvom on August 18, 2009, 08:21:48 PM: I ran the first half of the cam housing programs on Monday night. Since we have to share the lathe setups, I was limited to using the existing chuck jaws and could add only the boring bar to the tool holder. The existing 3-jaw chuck was set for 2.5" stock, so I needed to adjust the program to turn down from there as opposed to the 2" I had previewed. Since I couldn't drill the stock on the CNC lathe, I needed to cut off 1.5" thick discs of aluminum bar and then drill them 11/32 on the manual lathe.

Using the Haas CNC lathe there is a longish setup process where you touch off the X and Z coordinates for each of the tools your program will use. In this case I was using a turning/facing tool, the boring bar, and the parting tool.

Eventually I was ready to cut, but the first pass is always done by single stepping the program to make sure there are no gross errors that would break a tool or the machine. This took about 15 minutes to make the first piece.

Next I measured the critical dimensions. The boring depth was .008" too shallow as measured by a depth mic; since this is the critical dimension of the part, I needed to adjust an offset for the boring bar to correct for it. The second part was run a bit faster, and then remeasured to confirm the dimension is fixed.

The last two copies were run at full speed, taking 7 minutes machine time for each. One of the pieces received a slight ding, likely by hitting a chuck jaw when parted, so I have two "scrappies" and two good parts.

(http://www.pbase.com/kvom/image/116246644/large.jpg)

The second program to form the nose will likely need to wait until next week, as a new set of jaws needs to be bored to chuck the 1.675" diameter. The jawqs on these lathes are hydraulic and have a fairly short range of motion, so they need to be bored to fit a given depth and diameter, similar to soft jaws.

So producing the two good parts has taken approximately 6 hours, including programming, setup, and run time. It's interesting to work on, but obviously inefficient for small quantities.
Title: Re: Another Halo
Post by: kvom on August 19, 2009, 06:48:37 PM: My cheap Chinese 6" plain back chuck arrived today, so I spent the afternoon working to get it mounted on the rotary table. The first order of business was to verify the bolt circle of the 3 mounting holes in the back. I used the DRO to verify that the diameter is 142mm. The holes are threaded M8-1.25, so it was off to the hardweare store to purchase bolts of the correct length. After drilling the holes, I countersunk them with a .5" endmill, but the hole was still a few thou too small. A few minutes with the grinder reduced the heads so that I could attach the chuck to the plate.

With the chuck mounted, there is a 3/4" flange remaining for mounting slots. I milled these with the side flutes of a 1/2" endmill. Here's the result mounted on the rotab:

(http://www.pbase.com/kvom/image/116276193/large.jpg)

I removed one of the top jaws for measurement, as I intend to make a set of soft jaws. The next step will be to center the chuck body on the table, and then meaure the runout with the supplied jaws.
Title: Re: Another Halo
Post by: kvom on August 20, 2009, 07:13:11 PM: I got the rotab chuck dialed in today, although it took longer than it should have. I was holding the DTI in the spindle, but a better idea would have been to use the mag holder on the table. Indicating on the body of the chuck, I got it to within .001". Next I need to clamp a round bar and indicate to see how concentric the jaws might be.
Title: Re: Another Halo
Post by: kvom on August 23, 2009, 04:59:04 PM: I chucked one of the "bad" cam housings in the rotab chuck and measured the runout. It was .0015, so I "think" I will be within tolerances for building the parts that need the rotab.

Now for another issue, I needed to move the rotab closer to the center of the table. Now to re-center under the spindle, I no longer have access to the precise center hole of the rotab table. I think I will probably just use an edge finder againt the chuck body, or else on whatever workpiece is chucked.

I could also try using a DTI against the table's outer diameter, although that's a bit more time consuming. Since the chuck runout is small, I don't think I gain anything that way.

In the meantime, I ordered and received a parts list from Liney that has all the screws, bearings, balls, washers, etc. that is needed to complete the engine.
Title: Re: Another Halo
Post by: kvom on August 25, 2009, 11:18:16 AM: I turned the other side of the cam housings on the Hass lathe last night. It turns out one of my "good" ones was bad, so I have 2 good ones left. Hopefully I can drill all of the necessary hole (20 of them) without screwing up on at least one of the two.

(http://www.pbase.com/kvom/image/116502012/large.jpg)

Since I have machine time this week, I'm going to CNC the driveshaft as well. I cut off 4 2.25" pieces of 3/4" 12L14 before leaving. I'll face off at home, and turn them on Thursday if all goes well.
Title: Re: Another Halo
Post by: kvom on August 28, 2009, 09:31:14 AM: I turned the driveshaft on the Haas lathe at school last night. I started with 4 blanks and managed to get only one good part. Since I won't have access to the machine anytime in the near future, this is the last part for this engine I'll be able to make via CNC. However, at least I was able to run the two parts that have the critical dimensions.

(http://www.pbase.com/kvom/image/116610774/large.jpg)

I still need to drill and tap 3 holes on the part. I bought a package of 2-56 taps on eBay yesterday, so hopefully I won't fubar this.
Title: Re: Another Halo
Post by: kvom on August 31, 2009, 05:10:05 PM: I received the package of HSS 2-56 taps I bought on eBay a couple of days ago, so today I thought I'd test one before using it in anger.

The test victim was a piece of 1/4" aluminum plate. I drilled a through hole with the requisite #50 drill. One impression is that the Bridgeport spindle is not very sensitive with drills this small. I pecked it mainly looking at the swarf coming out of the hole.

Then off to the tapping stand. While the tap cut the threads very cleanly, again it was difficult to sense any feedback through the fingers. Nonetheless a SHCS screwed into the hole, so I can claim a success.

This engine uses over 100 of these screws, so I'd better get used to drilling small holes and tapping them.
Title: Re: Another Halo
Post by: kvom on September 03, 2009, 02:05:57 PM: Having made the soft jaws for the rotab, I wanted to use them for the cam housing. Here the portion that needs to be clamped is the 1" diameter nose. So I needed a pocket 1" in diameter wth a maximum depth of .400".

First, I positioned the rotab as close as possible so that its center is lined up with the mill's spindle. The jaws are clamped onto a steel round to keep them fixed. With a 5/8" end mill, I drilled down into the jaws .400" and turned the rotab 360 degrees. Then with the mill turning I locked the y-axis and moved the x-axis .05", then again rotated the table one full turn. I repeated this until I moves the X-axis 3/16", resulting in a pocket 1" in diameter. With the pocket formed, I then used the endmill to level the top of the jaws so that the piece would sit level when clamped. Here's the result:

(http://www.pbase.com/kvom/image/116847806/large.jpg)

Note that it is not sufficient to bore or drill the pocket using the mill, as the spindle may well be several thousandths off from the center of the rotab. Doing it this was ensures that the center of the pocket coincides with the center of rotation of the table.

Next I chucked the piece in the soft jaw pocket, and using a DTI in the spindle indicated its inner diameter. Thisa allowed me to line up the center of the cam housing with the spindle, and thus also with the center of the rotab. Now with the rotab in the horizontal position I can drill the 10 mounting holes, with each pair 72 degrees from the next. Note that I don't have to worry about drilling through holes into the jaws.

(http://www.pbase.com/kvom/image/116847811/large.jpg)

Once these holes are drilled, I will need to place the rotab in the vertical position without removing the cam housing, so that the pushrod holes can be drilled 72 degrees apart but 36 degrees from the mounting holes.

Now with the holes drilled:

(http://www.pbase.com/kvom/image/116856220/medium.jpg)

I put the rotab into the vertical position, square it to the table, and then center the workpiece on the Y-axis using an edge finder. I quickly discover a small "problem": the jaws are too close to the work and too long to reach with a drill in the spindle.

(http://www.pbase.com/kvom/image/116856221/medium.jpg)

So my original plan won't work. I didn't want to cut the soft jaws down far enough to allow the drill to reach, as I want to re-use the jaws for other parts.

The solution I came up with is to rotate the table so that the holes will be drilled between the jaws. I'll reclamp the work for each set of holes, and use the height gauge to ensure the proper alignment. I put pair of drill bits in the mounting holes, and then rotate the work so that the scribe of the gauge touches both; once in position I tighten the chuck.

(http://www.pbase.com/kvom/image/116856222/medium.jpg)
Title: Re: Another Halo
Post by: NickG on September 07, 2009, 06:30:24 AM: Good stuff, you're making good progress on this.

:thumbup:

Nick
Title: Crankcase
Post by: kvom on September 12, 2009, 06:59:31 PM: I have been working on the crankcase over the past few nights as time permitted. I'm sure John will make this a lot differently as he has 6 to do, but here's my effort.

Since I had a precision 1" bore in the rotab chuck's soft jaws, I chucked a piece of 2" dia. aluminum rod in the lathe and turned down one end to 1" diameter. On the other end I turned down 1" in length to the required diameter of 1.65". I then bored the interior to .75" for a depth of 1". I don't have a good boring setup for the lathe as yet, so further boring will be done on the mill.

Having previously dialed the rotab in to work on the cam housing, I was able to chuck the raw crankcase without further ado. I then used an endmill to enlarge the bore to just over 1".

(http://www.pbase.com/kvom/image/117181597/medium.jpg)

Since all of the holes to be drilled and tapped into the interior will cause burrs, I plan to bore to the final diameter of 1.25" after all the drilling is done. This will remove the burrs, which might be difficult to access otherwise.

Next the mounting holes for the cam housing were drilled.

(http://www.pbase.com/kvom/image/117181598/medium.jpg)

With the crankcase still in the chuck, I tilted the rotab to the vertical position. Here's my method of squaring it to the mill table:

(http://www.pbase.com/kvom/image/117181599/medium.jpg)

The mounts for the cylinders were machined next. I used a .75" endmill that was actually only .725", so each flat needed two extra passes to attain the necessary width.

(http://www.pbase.com/kvom/image/117181600/medium.jpg)

I spot drilled the five holes needed in each flat, then drilled and reamed the center hole to .500".

(http://www.pbase.com/kvom/image/117181601/medium.jpg)

Next there were 20 mounting holes to be drilled with a #50 drill. I have two of them, but somehow I have lost or misplaced one of them. Since there are a lot of holes this size to be drilled I hope I find the spare.

(http://www.pbase.com/kvom/image/117181602/medium.jpg)

Given the angles of the mounting holes, I just tapped them 2-56 using the guide I had previously made to tap on the mill or lathe. It turned out to be very easy to tap aluminum with this setup. The weight of the chuck was enough to start the tap cutting, and the taps cut very well. Less than minute for each hole.

(http://www.pbase.com/kvom/image/117181603/medium.jpg)

Trial fit of some screws:

(http://www.pbase.com/kvom/image/117181604/medium.jpg)

Unchucked the crankcase and put it on the tapping stand to tap the 5 holes for mounting the cam housing.

(http://www.pbase.com/kvom/image/117181605/medium.jpg)

The next step will be to bore the interior to final dimension. I will hold off parting off the crankcase as long as possible.

Maybe bogs can send me one of his cylinders for a test fit. :thumbup:
Title: Re: Another Halo
Post by: chuck foster on September 12, 2009, 07:07:40 PM: very nice build :thumbup: :clap:

i just didn't realize how small this engine was :bugeye: (well small to me) :)

keep up the good work (and photos) i will be following this build very close :nrocks:

chuck :wave:
Title: Re: Another Halo
Post by: sbwhart on September 13, 2009, 01:54:29 AM: Good job :thumbup: Nicely done and shown, great work with the RT :thumbup:

Have fun

Stew
Title: Re: Another Halo
Post by: spuddevans on September 13, 2009, 02:17:02 AM: Looking good there :thumbup: I'm enjoying watching this come together.

Tim
Title: Re: Another Halo
Post by: Gerhard Olivier on September 13, 2009, 03:16:19 AM: My mind is boggled

Amazing :bow: :bow: :bow:

Gerhard
Title: Re: Another Halo
Post by: Stilldrillin on September 13, 2009, 03:42:40 AM: It`s great to see a beautiful piece of engineering slowly emerging from the blank metal..... :thumbup:

David D
Title: Re: Another Halo
Post by: arnoldb on September 13, 2009, 04:11:15 AM: Those are excellent parts you're coaxing from stock :bow:
Good job :thumbup:

Arnold
Title: Re: Another Halo
Post by: bogstandard on September 13, 2009, 04:13:52 AM: Very nice indeed Kirk. You are doing a wonderful job.

It is making me very jealous now seeing how this is going.

It is a shame I can't restart such a big project for me at the moment, otherwise I would be letting you show me how to do it, as you have now taken over on showing people how easy this engine is to build.

John
Title: Re: Another Halo
Post by: NickG on September 14, 2009, 12:45:37 PM: Kirk,

Great stuff, this is going to be fantastic. Enjoying the show.

Nick
Title: Re: Another Halo
Post by: kvom on September 16, 2009, 12:59:13 PM: Here's the finishing touches on the crankshaft. I drilled the center hole on the lathe, and then mounted in the collet block to drill the two holes in the flange (these holes are used to attach the cams).

(http://www.pbase.com/kvom/image/117351136/large.jpg)

Then all three holes are tapped 2-56 at the tapping stand. Once again, the weight of the tap and chuck were enough to start the tap easily in the steel (12L14).

(http://www.pbase.com/kvom/image/117351134/large.jpg)
Title: Re: Another Halo
Post by: Darren on September 16, 2009, 03:09:00 PM: Looking good, gonna be another nice one from you again by the looks of it.... :clap:
Title: Re: Another Halo
Post by: kvom on September 17, 2009, 10:31:34 AM: I recently bought some 1-1/4" brass round via eBay for the cylinders, and since they arrived I decided to make the first one to see if my imagined machining sequence would work. It's a bit different from John's, but doesn't require any jigs.

The first step is to turn the basic shape. First turn the 3/4" upper section, then drill and ream the bore, and part off at 1" of length. I then reversed the piece in the chuck and faced the cut end. After measuring, I rechucked on the 3/4" section and turned the bottom to 1/2" diameter leaving .100" for the flange. That completes the lathe work for now.

(http://www.pbase.com/kvom/image/117369833/large.jpg)

I chucked the 3/4" end in a 5C collet block, mounted the block horizontally in the mill vise, and milled the flange to 3/4" square.

(http://www.pbase.com/kvom/image/117369835/large.jpg)

Next I mounted collet block vertically, located the center, and drilled the 4 mounting holes in the corners.

(http://www.pbase.com/kvom/image/117369836/large.jpg)

A quick test fit onto the crankcase:

(http://www.pbase.com/kvom/image/117369837/large.jpg)

Finally I reversed the piece in the collet block using a 1/2" collet, squared the flanges to the block using my height gauge, and drilled the mounting holes for the head.

(http://www.pbase.com/kvom/image/117369838/large.jpg)

Given that I have too many balls in the air project-wise, I probably won't make the other 4 anytime soon. In any case, I still need to tap the holes on the top, and cut the fins. I will definitely be following John's process for setting up the parting tool in the lathe for that. Once the fins are cut, the only remaining worj will be to shorten the 1/2" spigot to .100"; it's made ~2.5" initially to give more surface for chucking in the collet and lathe.
Title: Re: Another Halo
Post by: bogstandard on September 17, 2009, 11:01:28 AM: Very nicely done Kirk.

If I only had five cylinders to do, I think I would have used the same method as yourself.

Keep up the good work, because I will be snapping at your heels very soon.

John
Title: Re: Another Halo
Post by: kvom on September 28, 2009, 10:45:02 PM: Today I finished roughing out the other 4 cylinders. They all need the same finishing: tap the holes where the head mounts, cut the fins, and trim the bottom spigots to length. In the meantime, a poser shot to test fit on the crankcase:

(http://www.pbase.com/kvom/image/117677712/large.jpg)
Title: Re: Another Halo
Post by: chuck foster on September 29, 2009, 07:42:48 AM: looking good :thumbup: :thumbup:

chuck :wave:
Title: Re: Another Halo
Post by: Darren on September 29, 2009, 07:45:54 AM: I can see this is developing quite nicely...... :clap:
Title: Re: Another Halo
Post by: CrewCab on September 29, 2009, 05:27:02 PM: Top class work Kirk :thumbup: thanks for sharing.

CC
Title: Re: Another Halo
Post by: NickG on September 29, 2009, 06:03:55 PM: Looking very smart indeed!
Title: Re: Another Halo
Post by: kvom on September 30, 2009, 09:39:22 AM: Made a few more parts fpr the engine. First up was the crank and crank pin. I turned the crank from a piece of 1" 12L14. Faced the end of the rod, then turned .25" down to the .75" required diameter, and finally drilled the clearance hole (#43 drill .25" deep). The face needs to be countersunk to accept the flat screw. I should have used a screw to test the depth, but eyeballed it instead. I will need to deepen it so that it sits flush, else the conrods will hit the protruding screw.

Before parting it off, I took the rod off the lathe, mounted it in a 5C collet and collet block, and used the mill to drill the offset hole for the crank pin. This was actually unnecessary as I had to mill the reverse side after parting off, and I could have drilled the hole then. Once I had milled the reverse to achieve the required disc thickness, I needed to counterbore the center hole 3/16" diameter and .04" deep to match the crankshaft.

The crank pin was made from 3/8" drill rod. Here are the two parts:

(http://www.pbase.com/kvom/image/117754492/large.jpg)

and assembled onto the crankshaft:

(http://www.pbase.com/kvom/image/117754493/large.jpg)

Next up was finish boring the crankcase to 1.28". The interior finish isn't very good (using a brazed carbide boring bar). I think HSS would have been better. The holes make for an interrupted cut. I'm thinking now that drilling these after boring would be preferable, as with the thinner walls it's possible to debur the inner edges from the outside.

(http://www.pbase.com/kvom/image/117754494/large.jpg)

Test fit with the cam housing:

(http://www.pbase.com/kvom/image/117754495/large.jpg)

Final work for the day was to turn the push rods from .25" brass rod. This was not a difficult job, but was rather tedious as I need 10 of them. Each took ~10 minutes and three adjustments of the toolpost. First face the end, then turn to .125" diameter for a length of .465", and finally part off to .500". Once I had the 10 blanks, I mounted the shafts in a smaller collet and used a form tool to round off the heads, as shown in the plans. Had I not had the form tool, I could have also used my 1/8" corner rounding endmill mounted in a toolholder.

(http://www.pbase.com/kvom/image/117754496/large.jpg)
Title: Re: Another Halo
Post by: bogstandard on September 30, 2009, 10:09:22 AM: Kirk,

Nicely done, but unfortunately I have a bad comment to make.

There are no excuses for not deburring the job as soon as it is finished. That is a very basic machining practice, even for total newbies.

You will have no idea if the parts fit correctly together. As far as you know they do, but once deburred they might be as loose as anything. As for remachining the crankcase, how could you possibly hold it correctly, with previous machining burrs from ages ago still on the part. Plus the fact that you are liable to injure yourself on the rough edges. As soon as an operation is completed, and taken out of the chuck or vice, it should be fully deburred.

I am not being over critical, but posts should only show a very good example to new machinists, otherwise they are liable to pick up bad habits, by thinking if you do it, they should and can do it as well.

Bogs
Title: Re: Another Halo
Post by: kvom on September 30, 2009, 07:31:45 PM: Points well taken John. My intention with the crankcase is to remount it in the lathe and use scotchbrite to debur around the edges. I don't have a deburring blade small enough to enter the mounting holes on the cam housing, and I was thinking I will just counterbore them. Sitting here typing though, I think that my little countersink bit might be a good tool to debur them.

Since I don't have any brass the correct size for the heads, I'm planning to make the heads from aluminum and the valve cover from brass, just reversing the materials in the plans. Today I started on one of the heads. There is a lot of milling and drilling to do on a fairly small block of metal, but after a lot of studying the 3 separate drawings of the head I think I have it figured out. I did everything but drill and ream the holes for the pushrods, plus I need to acquire a 1/16" endmill to make the slot for the inlet. Pictures to come later. I spent about 5 hours getting to this point; for the remainder, using a vise stop to perform the same ops on all will save a lot of time. I still think it will take ~2 hours each.
Title: Re: Another Halo
Post by: bogstandard on October 01, 2009, 04:20:24 AM: Kirk,

I have already built a head inside my own, and really it is just a matter of backstop work and hole drilling in the right place, plus a little milling work, again using the backstop.

It looks to be a difficult part to make, but isn't really.

I usually scrape the burrs off, using an Olfa Laminate cutter. The blades are carbide, and if you are not silly and don't put too much pressure on, the blades will last for years.

http://www.olfatools.eu/product.php?id_product=84

or this

http://www.olfatools.eu/product.php?id_product=85

The cheaper one is definitely the best. Got to get me a couple more for stock.

John
Title: Re: Another Halo
Post by: NickG on October 01, 2009, 06:12:37 AM: John,

I am now looking at the 1/16" deep divet (more like 1/32" now it's healed) that came out of my finger when I cut it on the burr on the flywheel of my rocking engine. It's a permanent scar for sure and it'll serve as a good reminder to me never to do that again, but we don't want any more reminders.

I usually just deburr holes with a bigger drill or a csk and twisting it by hand and straight edges with a needle file. Guess I should probably get a proper tool.

Nick
Title: Re: Another Halo
Post by: kvom on October 01, 2009, 05:07:19 PM: Last night and today I made the first head. I still need a 1/16" endmill to finish a couple of minor operations, plus a 1/8" reamer, but this is it in essence:

(http://www.pbase.com/kvom/image/117808297/large.jpg)

As can be seen, lots of holes to drill in 4 of six sides. On the top are 7 holes: 4 through hols for mounting to the cylinder, one tapped hole in the center for attaching the rocker bracket, and the two holes on the little "plastforms" for the pushrods.

On "front" you can see 9 holes: 6 for attaching the valve cover, two holes for the valves, and one hole giving access to the cylinder. I still need to connect this hole to the right valve hole with an air passage, hence the need for the small endmill.

The bottom side has two holes that open to the cylinder. On the left it opens very slightly to the rear of the left (input) valve hole. On the right it joins with the small hole in the front.

The right side, a small exhaust hole joints to the right valve hole.

I didn't understand how the valves worked until I had made the head and understood the interconnections of the air passages. While the plans seem accurate, there is very little in the way of explanations or assembly instructions. The valving works as follows:

1) The two valve holes are counter bored and will contain a ball bearing that is larger than the inner part of the bore. When the pushrod for a hole is raised, the ball seals that hole, blocking any air passage. The left hole is the input side. The air inlet in the valve cover opens to this hole. When the pushrod descends (pushed by the rocker arm), it pushes the ball outward permitting air to enter the cylinder bore.

2) Conversely, the right ball valve prevents are from leaving the cylinder until its pushrod descends. Then the piston's upward motion pushed air through the right bottom hole, into the lateral hole, through the small air passage, into the right valve hole, past the valve ball, and out the exhaust hole.

Obviously the rocker arms must be out of phase by 180 degrees so that one valve is shut while the other is open.

The valve cover was made next. I started with a 1/4" piece of brass plate, but mistakenly milled it to 1/8" thickness before milling the countersinks for the mounting screws. I don't have a set of parallels that will allow me to hold it securely to mill these now, so I will likely throw this one out and make 5 more. The inlet hole should be a bit further to the right as well. In any case, here's how the head looks with the cover attached:

(http://www.pbase.com/kvom/image/117808298/large.jpg)

The hole in the left center is the inlet.

I then made a rocker arm bracket, but I'm not very happy with it either. The top can be optionally rounded over with a file or corner rounding bit, but I made it slightly too thin so that the cross hole is not centered. Once again I think it's a throwaway. In any case, this shows how it mounts to the head:

(http://www.pbase.com/kvom/image/117808299/large.jpg)
Title: Re: Another Halo
Post by: chuck foster on October 01, 2009, 08:45:11 PM: i have a question about this engine.
liney offers this engine as just plans ($29.00) or you can buy a machinists kit ($98.00) that has all the fasteners,bearings and metal. now my question is, is the machinists kit worth the extra bucks??

i want to build this engine but i won't be able to start building till after the new year.

chuck :wave:
Title: Re: Another Halo
Post by: bogstandard on October 01, 2009, 09:51:29 PM: Chuck,

If you have a look at my post,

http://madmodder.net/index.php?topic=1539.0

The first picture you come to shows the engine fasteners pack. The sectioned package on the right.

Then you will have all the materials as well. It is up to you whether it is easy for you to source the parts and materials yourself, or take the easy way out and have everything to hand.

I have attached the material list from the plans to show you what you will actually get for your extra bucks.

If you do have a problem sourcing materials, it looks to be a good buy.

BTW, the tools don't come in the pack.

Bogs
Title: Re: Another Halo
Post by: kvom on October 01, 2009, 09:58:33 PM: I bought the plans and fasteners, but not the materials. There are a lot of 2-56 screws of different lengths, plus lots of other bits. I think I would have spent a lot of time trying to figure out what I needed, then actually getting them.
Title: Re: Another Halo
Post by: kvom on October 04, 2009, 10:50:25 PM: Yesterday and this morning I had high hopes of finishing 5 cylinder heads. I had milled the profiles, spot drilled all 18 holes on each, and had drilled the 4 though mounting holes on each as well. The first task this morning was drilling the 2 valve holes. The plans call for a 5/32 drill, but mine is missing so I decided to use the nearest number drill (#23). This hole is drilled to a depth of .400", and then a #8 (.200 nominal) is used as a counter bore. Unfortunately, when i did the first hole with the #8, there was no swarf. After some investigation, I found that the tip of the #23 had broken off halfway, and somehow this resulted in oversize holes. Effectively, all 5 heads were now ruined. I was not a happy camper, although I had managed to refine the machining process so that I had wasted only 3-4 hours on all 5 rather than the 3-4 hours I spent making the first one solo.

The other sad thing is that I had two #23 drills; the good one wa sitting in the space 5/32 in the drill index, and had I used that one all would be well.

Rather than restart the heads immediately, I decided to work on the valve covers. A couple of hours work resulted in a satisfactory result:

(http://www.pbase.com/kvom/image/117928320/large.jpg)

Nothing too difficult in machining these, given a vise stop and a DRO.
Title: Re: Another Halo
Post by: bogstandard on October 04, 2009, 11:16:33 PM: Nice one Kirk. It is coming along very nicely

This is one area I will be differing from yours. Instead of the tube spikes (real nice quality, and supplied in the kit of parts), I will be making rigid manifolds and flanges. It will be the same for the exhausts, instead of just a hole in the side of the head, mine will have exhaust stubs. It is all to do with making ones engines unique.

John
Title: Re: Another Halo
Post by: kvom on October 06, 2009, 04:24:40 PM: I too was thinking of something other than a little hole for the exhaust, but it will be an "add-on" once the engine runs. As for a rigid manifold, I suspect I could still use these flanges as long as the input pipe fits the 6-32 threads. That too would be an add-on.

Yesterday I started making the rocker brackets, and today I drilled the holes. I'm still waiting for my set of O/U reamers to arrive; when they do I can ream the cross hole .124".

(http://www.pbase.com/kvom/image/118001693/large.jpg)

I also finished the milling part of a set of new heads, but didn't feel up to the marathon of drilling they need, so I set them aside for another day.

Then started on the bearing carrier. I had a piece of aluminum that just needed a bit of turning on the lathe to arrive at this:

(http://www.pbase.com/kvom/image/118001700/large.jpg)

The left side is turned to 1" diameter so that it would chuck accurately in the soft jaws on the rotab. The right end was faced; it's diameter is about .200" larger than the final diameter of the carrier. Then I invoked Marv Klotz's flywheel program to get parameters for milling the spokes. Everything is drilled/milled .150" deep or more:

(http://www.pbase.com/kvom/image/118001709/large.jpg)

Once I obtain the 3/8" under reamer for the center hole, I will turn the outer diameter on the lathe and part off the carrier at the specified .125" thickness. I did countersink the mounting holes after the picture was taken as they use flat head screws.
Title: Re: Another Halo
Post by: kvom on October 09, 2009, 09:28:33 PM: Made the cams:

(http://www.pbase.com/kvom/image/118110076/large.jpg)

I turned some brass rod down to .780" and drilled the center hole, then mounted it in the rotary table to mill the rest of the profile and drill the mounting holes. Then it was back to the lathe to part off two "slices". Finally I milled the cams to the desired thickness.

Here they are mounted on the driveshaft:

(http://www.pbase.com/kvom/image/118110077/medium.jpg)

The dimensions given result in a very precise, tight fit. To get the screws to line up with the taped holes in the shaft I needed to file the center hole slightly to give some wiggle room. I also think a #43 drill for the mounting holes would be preferable to the #44.

One issue to resolve at assembly time is the angle the crank pin needs relative to the cam lobes. The cam nearest the end drives the input valve, so I'm guessing that the valve should start to open somewhat just before TDC. Comments?
Title: Re: Another Halo
Post by: CrewCab on October 10, 2009, 01:46:19 PM: Excellent work Kirk :beer:

The flywheel is looking good and nice use of the mill ............... plus Marv's input of course, well done sir :headbang:

About the Cam's :scratch: ................... yes. it looks like the inlet valve will begin to open a little over 11^o before TDC, however I seem to be missing something in the drawings ............. is there a dimension short ............. how do you locate the intersection of the 20^o angle with the .78" diameter, obviously once that is correctly machined the .68" diameter is straightforward to machine .................. not a criticism by any means Kirk, perhaps just my ageing brain cell's refusing to co-operate .

Again ................. top class work mate :bow:

CC
Title: Re: Another Halo
Post by: kvom on October 10, 2009, 02:26:39 PM: The straight sides are .340 from the center, so I move the x-axis +/- .340 plus the radius of the cutter, rotate the table +/- 10 degrees, and cut straight with the y axis. Then for the .340 radius portion, I set the x-axis to 0, rotab to 0 degrees, and touch the endmill side flutes to the work. Then in theory I just need to move the y-axis in .050" and rotate the table. In practice I cut in .045" first and measured the diameter before taking the final cut.

The crank pin can be installed at any angle to the cams. TDC should occur then the pin is directly below the cylinder's axis, so my question is whether the valve should open before, at, or after TDC?
Title: Re: Another Halo
Post by: CrewCab on October 10, 2009, 02:42:36 PM: Quote from: kvom on October 10, 2009, 02:26:39 PM
The straight sides are .340 from the center,

Got it .... (an Eureka moment for my grey matter)...... :med: ............... thanks Kirk, looking forward to the rest :bow:

CC
Title: Re: Another Halo
Post by: bogstandard on October 10, 2009, 04:48:25 PM: If you go to here, how to cut the cams on the RT is explained step by step.

http://lineymachine.googlepages.com/halobuildinginformation

Bogs
Title: Re: Another Halo
Post by: CrewCab on October 10, 2009, 04:55:54 PM: Thanks John, that table of diagrams is just spot on :thumbup:

CC
Title: Re: Another Halo
Post by: kvom on October 13, 2009, 07:27:54 PM: After a weekend spent mostly watching the Presidents Cup golf matches on TV and some assorted honey-dos, I spent the afternoon in the shop making a little progress.

The first order of business was to get the bearing retainer finished. Since I now had a 3/8 under reamer, I mounted the piece in the lathe and reamed the center hole to .374. Then I parted off the part and spend some time cleaning up the mounting holes; the tapping stand was useful for this. Then there was the obligatory trial fit:

(http://www.pbase.com/kvom/image/118269226/medium.jpg)

Looks as if I need a deeper countersink for the screws, and some filing to make the spokes a bit nicer. I did a quick test of the bearing supplied by Liney, and it looks as if it will be a nice fit - not loose but not terribly tight either.

Not being overly ambitious, I decided to just make the rocker pins. Although these are pretty darn simple, they were tedious to make with lots of ins and outs on the collet chuck. First, hacksaw off 5 pieces of 1/8" brass rod a bit longer than the finish length; next face all 10 ends to get accurate length measurement. Then face off to final length. Now I needed to center drill each end, as I was not sure that I would get a straight hole drilling through from one end. So I drilled halfway, then turned around and drilled through from the other side. The final operation was threading each end, using the bushing I made to fit the tapping chuck. So I probably spent two hours just to make these 5 small, simple parts.

(http://www.pbase.com/kvom/image/118269227/large.jpg)
Title: Re: Another Halo
Post by: kvom on October 16, 2009, 07:42:43 PM: More shop time making little fiddly parts the past few days.

Since I obtained my O/U reamers, I reamed the cross hole of the rocker bracket and inserted the rocker pins. Not a press fit, but I suppose brass rod isn't necessarily on size.

(http://www.pbase.com/kvom/image/118361394/large.jpg)

Next I started on the rocker arms. I first took a 6x6" piece of 1/4" aluminum plate and cut off as slice that I machined to 1" wide. I then milled the profile of the arms. The sides of the center section were milled with a 1/8" ballend endmill to obtain the rounded corner profile. I then used a 1/4" endmill to slice off 10 pieces. At the end of the cut the pieces would snap off leaving a large burr that would need to be milled off later.

(http://www.pbase.com/kvom/image/118361397/large.jpg)

The next machining steps required the use of soft jaws on my Kurt vise, as both the rockers and the connecting rods to follow are 1/8" thick. After mounting the jaws, I milled off the existing slot with a 1/8" endmill to get a flat starting point. Then I clamped a 6" rule between the jaws to allow clamping room later, located the center of the slot with the edge finder, and milled a 3/32" deep slot with a 1/8" endmill.

(http://www.pbase.com/kvom/image/118361398/large.jpg)

After positioning a vise stop and locating the x-axis with the edge finder, I was able to mill off the burr from each piece, and then drill the vertical hole that will accept the pushrod:

(http://www.pbase.com/kvom/image/118361399/large.jpg)

The same setup was used to spot drill, drill, and ream the cross hole for the rocker pin.

(http://www.pbase.com/kvom/image/118361401/large.jpg)

Finally, I cut four pieces of 1/8" square brass rod (using a wire cutter is quicker than hacksawing), and used the same vise slots to mill to length, drill the cross holes, and finally mill the slot in the end (1/16" endmill):

(http://www.pbase.com/kvom/image/118361402/large.jpg)

For those who haven't tried soft jaws and have a vise with removable hard jaws, I can recommend them for holding thin pieces where parallels are impractical. Note that you can drill into the jaws through the pieces, which is not a good idea with hard jaws.
Title: Re: Another Halo
Post by: NickG on October 17, 2009, 04:47:06 AM: Wow Kirk, you're marching on ahead with this one! Looking great :bow:
Title: Re: Another Halo
Post by: kvom on October 17, 2009, 08:21:12 AM: One of these days I need to get my nerve up and cut the fins on the cylinders as per Bogs' recipe. ::)
Title: Re: Another Halo
Post by: bogstandard on October 17, 2009, 09:36:48 AM: Why did you think I did those cylinders first?

Always do the difficult bits first. If you can get those finished, then it is all downhill for the rest of the build.

That is why so many builds end up under the bench. They do the easy bits first, then when they come to the hard, they have had enough and just give up on it.

Bogs

BTW, I hope you made a few spares.
Title: Re: Another Halo
Post by: Darren on October 17, 2009, 10:11:07 AM: You are a bugger John ..... make him feel good eh .... :med:
Title: Re: Another Halo
Post by: bogstandard on October 17, 2009, 12:14:44 PM: Darren,

I explained all about getting the hard bits out of the way on my Halo post. Also, I have yet to see on any of the Paddleducks engine builds, one with the steam control valve fitted and working. Maybe because that is one of the most difficult parts to make. It just so happens that it has to come at the end because other components are required to build it. So once it has had it's initial run on air, without the controller, they seem to be forgotten about.

If Kirk gets the message and has only made just enough cylinders, he will do a bit of practicing first on bits of bar. Then when confident about the result, go for it.
I started out with 23 I think, and lost two on the journey. That is an attrition rate of 10%, and I am experienced in making things like that. Kirk needs to get the practice in first, not only in cutting the grooves, but grinding up the tools to do the job.

Hence the warning.

John
Title: Re: Another Halo
Post by: Darren on October 17, 2009, 12:44:27 PM: Tis OK John, I knew exactly where you were coming from .... :thumbup:
Title: Re: Another Halo
Post by: kvom on October 17, 2009, 01:18:53 PM: Quote
practicing first on bits of bar
That is my plan, as it happens. :headbang: I didn't make a spare cylinder; I decided that I would not gain any efficiency in making extras as it would take me as long to make a replacement as a spare. Given John's procedure for truing the tool, there is really no reason that cutting the fins should be an issue. (knocking on wood as I type this).

Once I get the master rod made (current work item, that for me in one of the harder pieces), I will need to suck up and finish the cylinders. I don't want to make a piston for a cylinder that needs a do-over.

As for the paddleducks build, I ran out of solder and am waiting for my order to arrive to finish the valve. For me, at least this far, the machining/fabricating work is more "fun" than the debugging. However, I promised myself not to start another build after the halo before I get the paddleducks working with the valve and some bling done too.
Title: Re: Another Halo
Post by: bogstandard on October 17, 2009, 05:54:29 PM: Kirk,

I wasn't :poke: you specifically, it was just a comment about what is happening with the Paddleducks engines.

It is my fault really, for doing a difficult piece at the very end. But that is the only way it could be done, to accurately make it physically fit the engine.

Bogs
Title: Re: Another Halo
Post by: ozzie46 on October 17, 2009, 09:19:25 PM: Quote from: bogstandard on October 17, 2009, 12:14:44 PM
Darren,

I have yet to see on any of the Paddleducks engine builds, one with the steam control valve fitted and working.
John

Ok John, here it is.

(http://i661.photobucket.com/albums/uu334/ozzie46/th_MOV02783.jpg) (http://s661.photobucket.com/albums/uu334/ozzie46/?action=view&current=MOV02783.flv)

I didn't find the control valve all that difficult to build. :dremel: Just a little bit time consuming to get the spool to length , took me about half an hour. Then again maybe I got lucky. :D

Sorry about the quality of the video. I'm still not to versed on them yet.

Ron
Title: Re: Another Halo
Post by: bogstandard on October 18, 2009, 01:49:38 AM: Absolutely wonderful Ron, you have just made my day.

Many thanks for showing it to us.

Another first.

John
Title: Re: Another Halo
Post by: kvom on October 18, 2009, 01:06:54 PM: Yesterday and today I worked on the most challenging part thus far, the master rod. Because of the irregular shape I figured I needed a jig to hold it. First I reduced a small piece of 1/4" brass to .375" wide by 1.25" long and drilled the holes needed for the wrist and crank pins. After reaming the crank pin hole, I machined it to 1/16" thickness.

For the jig, I found a 3" diameter disc of aluminum about 3/4" thick. I turned one side for a 1" diameter spigot that would mount on the rotab, and then turned the other side with a small .125" spigot that would be a tight fit for the crank pin hole. Once mounted on the rotab and centered under the spindle, I set the rotab to 0 degrees and drilled a .063" hole .850" from the center. I then could mount the workpiece on the center spigot and hold it laterally with a piece of 1/16" drill rod. I then drilled the 4 holes to which the other connecting rods will be pinned:

(http://www.pbase.com/kvom/image/118430547/medium.jpg)

Next using a 1/8" endmill I tried to carefully machine the profile using a combination of linear and rotary motions. Unfortunately it seems I had a slight undercut on one side.

(http://www.pbase.com/kvom/image/118430549/medium.jpg)

I trimmed the tail to length leaving a workable, although less than perfect, master rod.

(http://www.pbase.com/kvom/image/118430550/medium.jpg)

Some lessons I learned. I had intended to drill and tap a hole in the tail as a hold-down (for that reason it was left long). When I first mounted it on the jig it was very solid, so I neglected that step. On a do-over I would do so as the piece did have a tendancy to lift when milling the tail portion. Rather than the spigot in the center of the jig, I would just drill a hole and insert some 1/8" drill rod.

If, like John, I needed to make multiples, I would sandwich all of the pieces and drill/mill all at the same time. I think using a larger endmill and calculating the toolpath for a single cut of the entire profile would be better than the incremental milling I used. I'll be interested in seeing how John approaches this part. I don't really see the need to shape the head as the plan shows unles I find some binding with the rod ends once assembled.
Title: Re: Another Halo
Post by: bogstandard on October 18, 2009, 02:59:46 PM: Kirk,

I will only be able to make two the same, all the rest will be different.

John
Title: Re: Another Halo
Post by: kvom on October 18, 2009, 05:54:41 PM: Quote
I will only be able to make two the same, all the rest will be different.

That's true - different number of holes for the conn rods.

And since John goaded me into action:

Since my house was invaded this afternoon by 7-8 teenagers at the invitation of my daughters, I decided to hide out in the shop. It was finally time to turn the fins in the cylinders, as they had been waiting since 9/28 to be finished up. Bogstandard has a fine writeup on setting up the very thin parting tool (.025", no relief), and I followed it pretty much as written. Since the tool needed a surface grinder to create, others attempting this build might choose to use a wider, commercial tool and cut fewer fins (or no fins at all). I was able to chuck the parts in my Jacobs Rubberflex collet chuck, and the cuts were surprisingly easy.

Like Bogs I had written down a list of X-Y coords for each cut, and it took only about an hour or so for all 5. Having a DRO on the lathe makes this a much easier proposition. Then I reversed them in the chuck to cut down the bottom spigot to length. One thing I did differently was using a 1/16" parting tool to turn down the three bottom fins; this avoided the thin wires that would result from using the thinner tool.

(http://www.pbase.com/kvom/image/118444230/large.jpg)

My list of to-do parts is getting smaller. I still need to drill the many, many holes in the heads and make the 5 pistons, and then I can think about some assembly, a base for mounting, and some sort of air manifold.
Title: Re: Another Halo
Post by: bogstandard on October 18, 2009, 08:03:12 PM: Nicely done Kirk.

DRO's and surface grinders do make life a lot easier when doing a job like this.

I do still have the extra tools I ground up for doing the finning job, so if anyone wants to build one of these engines, and doesn't think they could grind up a tool to do the job, I am sure that one could find it's way to you.

Bogs
Title: Re: Another Halo
Post by: kvom on October 18, 2009, 10:30:30 PM: I could send mine to someone on this side too.
Title: Re: Another Halo
Post by: kvom on October 21, 2009, 11:45:17 AM: I started drilling holes in the remade heads yesterday, and "sacrificed" the first one. Once again the valve holes presented the problem. The drawings specify the depth to cut, but show a flat bottom hole. The first holes I drilled I used the points to set the depths, but doing this the valve ball sits too high for the plunger to contact. So I reset both the initial hole and counter bore to not count the point. The first hole then goes into the side mounting holes. This is probably not an issue, but it's also possible I don't need that full .4" depth anyway. A bigger problem was that the counterbore was probably a 1-2 thou. too deep and intersected the plunger hole; I think this would make the valve leak. So I now believe the solution is to use an endmill in order to achieve a flat counterbore. The plan specifies .200 counterbore. A 3/16" endmill followed by a #8 reamer should work.

I'm out of town the rest of the week, so I'll try it next week.

Of course, all of this is of little interest unless you're planning to build this one too. :coffee:
Title: Re: Another Halo
Post by: kvom on October 21, 2009, 10:08:31 PM: I had a little more shop time before leaving for the long weekend, so I "caught up" on some tapping. This model needs a lot of tapped holes. Each of the 5 cylinders and their attached parts total 20 2-56 holes. Without the tapping stand I made a short while ago this would have been mission impossible.
Title: Re: Another Halo
Post by: shred on October 21, 2009, 10:37:43 PM: Thought I'd posted my video of the PD engine running with the valve spool and all.. but it turned out the only posted video shows it running with the valve on, but not operation of the valve ltself.. sorry Bogs :scratch:

Anyway, kvom, those parts are looking good and the notes are very useful as well. Keep it up.
Title: Re: Another Halo
Post by: kvom on October 29, 2009, 07:14:35 PM: After a 4-day weekend offroading the Jeep and 3 more days doing various maintenance work, I finally had an afternoon in the shop to get back to the engine.

First I finished all of the remaining drilling on the 4 headers (I will need to remake the 5th). Then I put one of them together completely along with the cylinder. Here's a looksee:

(http://www.pbase.com/kvom/image/118842865/large.jpg)

Originally I was going to leave the valve cover thicker than the plans, as I had made them from .25" thick brass plate. However, I needed to attach them with the shortest screws, so the options were to machine them thinner or cut the counterbores deeper. FWIW, I milled the counterbores with a 3/16" endmill; the plans show using a 1/8" endmill, but since the head of the screw is larger than that milling the bores is more complicated/tedious.

Some of the brass plungers were a bit too large to fit the holes, even though I measured them at .125" and the holes were reamed with a .126" reamer. Once they're machined they are a PITA to hold and polish down to size (I used a needlenose plier). So a recommended alternative would be to make the heads first and test for fit on the lathe before parting off and machining the heads.

Next step is to clean up the interiors of the cam housing and crankcase, plus part off the crankcase and make some pistons. Then it will be time for a trial assembly. I also need to start thinking of a mount design.
Title: Re: Another Halo
Post by: kvom on October 30, 2009, 09:36:27 PM: I had another full afternoon in the shop. Today I started with the pistons. Chucking some 1/2" diameter aluminum rod, for each I turned 1/2" length down to .375 and individually fitted each to its own piston, trying to attain a rough sliding fit. Then I parted each off,

To finish a piston, I chucked it in a 5C collet block with .25" exposed, then placed the block vertically in the mill vise. I used an edge finder the first time to find the center. First operation was to mill off the nub from parting and bring to length.

(http://www.pbase.com/kvom/image/118878279/medium.jpg)

Then with a 1/8" endmill (1/16" for the master piston) I cut a slot .200" deep, then widened the slot .003" on each side with two more passes.

(http://www.pbase.com/kvom/image/118878280/medium.jpg)

Then it was a simple matter to chuck the collet block horizontally and spot drill/drill the cross hole for the wrist pin. Once removed from the collet and deburred, I was able to assemble the conrods to the pistons using the pins supplied by Liney. The holes are not a press fit, but I doubt that's critical. Here's a "family" portrait:

(http://www.pbase.com/kvom/image/118878281/medium.jpg)

The pistons still need a bit of toothpaste lapping to slide smoothly. I didn't cut any oil grooves but I did chamfer the tops of the pistons.

After smoothing the inside of the cam housing with Scotchbrite, I wanted to do a trial assembly of the front portion of the engine. The first task was to machine the bearing carrier to its planned thickness of .125". I had previously parted it off oversize and needed to removed .016" from the back. To do this I decided to use my "new" chuck with soft jaws on the lathe. I had made the jaws over a month previously, but this was the first opportunity to try it.

First, I machined a pocket .100" deep and 1.275" in diameter to match the part. This allowed me to then chuck the disc securely and take the facing cut:

(http://www.pbase.com/kvom/image/118878283/medium.jpg)

Now after deburring, I laid out the components for assembly:

Cam housing, front bearing, driveshaft, rear bearing, and bearing carrier:

(http://www.pbase.com/kvom/image/118878284/medium.jpg)

The rear bearing is a tight fit to the bearing carrier:

(http://www.pbase.com/kvom/image/118878285/medium.jpg)

Then screw the bearing carrier to the cam housing to complete the assembly:

(http://www.pbase.com/kvom/image/118878286/medium.jpg)

It's important that the bearing carrier press both bearing firmly against the driveshaft to eliminate any slack but not so that the "preload" causes binding. I need to do some tweaking here. I also noticed a few more issues to fiddle with.

1) The plunger holes are slightly too small for the supplied ball bearings to slide freely, so may need deburring or mild filing.

2) The rear cam seems a bit too far forward and may be interfering with the front plungers. I may need to add a shim.

3) The crank is not sitting perfectly straight on the end of the shaft. I suspect the counterbore bottom is not flat. In any case, the thickness of the crank or depth of the counterbore can be modified to center the conrods under the cylinders, so I will hold off until I'm ready to fit the crankcase.
Title: Re: Another Halo
Post by: chuck foster on October 30, 2009, 11:07:38 PM: looking good kvom :thumbup: :thumbup:

there is allot of parts to this engine and they seam to be kinda small :bugeye: but you are making it look easy.

cant wait to see this one run :ddb: :ddb: :ddb:

chuck :wave:
Title: Re: Another Halo
Post by: Darren on October 31, 2009, 06:30:26 AM: Looking good there Kirk, that looks like a fiddly engine with all those tiny bits, :thumbup:
Title: Re: Another Halo
Post by: kvom on October 31, 2009, 06:12:04 PM: I had a couple of hours before the Halloween visitors start arriving to tweak the cam housing issues.

I discovered upon inspection that the front cam was not seating flat against the driveshaft flange. With tight tolerances on all the parts, the clearance holes were not large enough to allow the screws to enter perfectly straight. I drilled them out with a #43 drill as opposed to the original #42, and with some careful tightening both cams set flush.

Since the camming surfaces are so close to the inner diameter of the cam housing, it's important that the shaft and cams be as perfectly centered as possible. How the bearing carrier is screwed to the housing is important, as it seems that the slightest cant in the carrier can cause the cams to rub. So tightening the screws evenly all around going in circles was necessary. I marked both the carrier and housing to ensure that any reassembly matches up the same set of holes. When assembled, the bearing preload seems good, so I don't think any adjustment will be needed.

I cleaned up the pushrod holes, and now the supplied ball bearings and my brass pushrods fit nicely.

I also parted off the crankcase and turned the back flush, so that I can start thinking how to build a base.

(http://www.pbase.com/kvom/image/118878287/medium.jpg)

Darren,

The size of the parts hasn't been as intimidating as I thought at first. Having soft jaws on the lathe, vise, and rotab really helps, as otherwise clamping would be an issue on some things. One fiddly issue for me is the size of the screws; I have to be really careful not to drop any as there are not a lot of extras in the kit.
Title: Re: Another Halo
Post by: NickG on October 31, 2009, 07:44:02 PM: Yeah looks far too fiddley for me! Well done, can't wait to see this in action!
Title: Re: Another Halo
Post by: kvom on November 01, 2009, 08:41:48 PM: Got into the shop around noon, and decided to verify that the pushrods would correctly activate the rocker arms and valves as designed. The pushrods are just 1/16" drillrod 1.4" long, so I cut off a couple with wire cutters and filed the ends. Here's the assembly with one cylinder:

(http://www.pbase.com/kvom/image/118956736/medium.jpg)

It seems to work! At least the plungers that activate the valves go up and down. It takes a fair amount of force to turn the shaft with just fingers. As Liney suggestes, I will need to attach a small chuck or the equivalent to turn it manually with all 5 cylinders mounted. I may need fewer turns on the springs as well.

Given that assembling further without something to hold the engine securely would be difficult, I spent the rest of the session making the first part of an engine mount. First, I took the piece of aluminum from which I parted the crankcase, faced it on the lathe, and then drilled and tapped 5 holes to match the rear mounting surface of the crankcase.

(http://www.pbase.com/kvom/image/118956740/medium.jpg)

Next, I found a piece of aluminum plate that had a hole in a useable spot, and with the aid of a little trig and the DRO, I drilled holes to match the jig.

(http://www.pbase.com/kvom/image/118956744/medium.jpg)

Then after enlarging the hole a bit on the mill, I mounted the plate on the jig...

(http://www.pbase.com/kvom/image/118956749/medium.jpg)

... and milled the hole to match the innder diameter of the crankcase.

(http://www.pbase.com/kvom/image/118956755/medium.jpg)

Successful test fit:

(http://www.pbase.com/kvom/image/118956759/medium.jpg)

Some more milling, flycutting, on the rotab and vise yielded this:

(http://www.pbase.com/kvom/image/118956764/medium.jpg)

A test fit of the crankcase and a couple of cylinders to show that there is clearance for air supply:

(http://www.pbase.com/kvom/image/118956769/medium.jpg)

I won't be able to complete the mount until I get a propeller and determine the necessary height above the base, but this part will be very useful in assembling and testing.
Title: Re: Another Halo
Post by: kvom on November 08, 2009, 08:24:53 PM: Since I blew a start cap on the RPC this week, the lathe was out of operation until this weekend. Once I got things back together, I finished remaking the crank, and it now sits square on the shaft. I also managed to file the ends of the conrods so that they will assemble with the master rod and the crank pin.

So now comes the problem of assembly. I discovered that there is no way to insert the assembled conrods/pistons with the cylinders attached. So my plan is to insert the pistons into the clyinders with the conrods attached, and try to assemble the rods inside the crankcase. If that proves too hard I can try it without the cylinders and and/or pistons, and then install the cylinders over the pistons.
Title: Re: Another Halo
Post by: kvom on November 09, 2009, 06:20:23 PM: After a lot of unsuccesful fumbling, I finally figured I would never get the conrods attached while they were in the crankcase. So I disassembled everything, and was successful in pinning the rods together.

(http://www.pbase.com/kvom/image/119225788/medium.jpg)

The pins themselves were a bit of a struggle: 1/16" drillrod .150" long. In order to get them cut to length I made a "jig" by milling a small piece of aluminum .15" thick and drilling a 1/16" through hole. I inserted some drill rod, cut it off close with a wire cutter, and then filed it flat to the jig. Still, these are the smallest "parts" I've ever had to deal with.

With the rods assembled, they can be inserted into the crankcase via one of the cylinder holes:

(http://www.pbase.com/kvom/image/119225557/medium.jpg)

Then I attached the front section to the crankcase and screwed the crank pin to the crank.

(http://www.pbase.com/kvom/image/119225564/medium.jpg)

I discovered that I needed to file the profile of the master rod so that the screw attaching the crank to the crankshaft is accessible with the rods attached. This is because the timing is adjusted by rotating the rods relative to the cams.

Next session I'll attach the pistons to the rods and then the cylinders to see what kind of friction there is in the works.
Title: Re: Another Halo
Post by: kvom on November 11, 2009, 05:03:44 PM: This afternoon I took a short time to attach the pistons to the conrods, and then slide the cylinders over the pistons to attach them to the crankcase:

(http://www.pbase.com/kvom/image/119288252/medium.jpg)

(http://www.pbase.com/kvom/image/119288261/medium.jpg)

After a bit of twiddling the engine turns very smoothly with finger pressure, except if the screw for the crank pin is turned down tight, binding the conrods.

I'm pretty sure I knw the reason for this. When I milled the crankcase I left the front edge an extra .01" or so from the center line, intending to have room for adjustment later. Well, the time for adjustment has arrived. There are several options for aligning the conrods:

1) Mill a bit off the front of the crankcase
2) Make the crank disk thicker
3) Make the crank pin longer

I think the one I'll choose eventually is none-of-the-above. The next time I disassemble the engine I will make an insert a thin brass washer between the crank pin and the disk.

I don't think leaving the crank pin screw slightly loose is a good option, as the rotation of the engine will tend to cause the screw to tighten.

I received a package from Enco today with a supple of 1/4" hose barbs, so I will think about making a manifold to supply air to all 5 cylinders.
Title: Re: Another Halo
Post by: kvom on December 03, 2009, 09:33:03 PM: I have been spending shop time working on the Jeep, but decided to finish a small step on the Halo.

In order to provide a grip to set the timing as well as provide some flywheel effect during tuning, Linety recommends attaching a small weight to the propeller shaft. I had recently gotten a broken driveshaft from an offroad buddy, and decided to use the splined end to make this. I mounted the shaft in the lathe and faced the end, drilled a 1/4" hole, and then sliced off a 1" piece on the bandsaw. I then used the mill to remove the saw marks.

The next step is to provide a means of securing the weight to the shaft. Based on an earlier suggestion, I obtained some #4 lead shot from a shotgun shell. These will be used to press against the shaft. Since the shot measure 1/8" in diameter, I drilled a 1/8" hole through to the center. Given the splines on the sides, the hole was made with a 1/4" endmill to create a flat spot followed by a 1/8" endmill to mill the hole.

(http://www.pbase.com/kvom/image/119971213/medium.jpg)

I need a set screw to hold the shot in place, and a 8-32 is the next size up where the tap drill is > 1/8". The particular steel was quite hard to tap, as it feels "sticky". Fearing breaking off my tap, I managed to make only about 4 threads, so I hope these are enough. Here's a shot of the weight mounted on the engine shaft:

(http://www.pbase.com/kvom/image/119971214/medium.jpg)

The brass rod was there to tamp down the lead shot into the hold. In didn't have a 8-32 setscrem on hand, so that is another item on the shopping list.
Title: Re: Another Halo
Post by: chuck foster on December 03, 2009, 09:36:19 PM: looking good kvom, i just didn't fully understand how small this engine was :bugeye:
you have done a great job posting pictures and the write up's that go with the pictures.................thanks.

chuck :wave:
Title: Re: Another Halo
Post by: Russel on December 04, 2009, 12:14:04 AM: Wow, that shortblock is looking great!

One of the things that I really like about the 5 cylinder halo is the sound that it makes. I'm currently working on Elmer's No. 11 three cylinder radial, hoping that I haven't bitten off more than I can chew. But, after watching a video of a 5 cylinder halo, and hearing it...I see one in my shop sometimes in the future.

...following your build with great interest!

Russ
Title: Re: Another Halo
Post by: Bernd on December 04, 2009, 10:59:31 AM: Kirk,

Looking real good so far. Cann't wait to see and hear her run. :thumbup:

Bernd
Title: Re: Another Halo
Post by: kvom on December 04, 2009, 07:02:10 PM: To get a runner, I will need to supply air to all 5 cylinders individually. So I made this simple manifold for a small piece of aluminum bar.

(http://www.pbase.com/kvom/image/119995850/medium.jpg)

Drilled 3 through holes and threaded the 6 openings 1/4-27 NPT. Then 5 hose barbs for 1/4" plastic tube and ther 6th hole for the regulator line.

The "tuning" instructions are to do each cylinder individually, where you are primarily setting the length of the pushrods so that the input and output valves open and close properly. I realized that I could do this with the tubing attached to all of the cylinders by having only the cylinder being tested have pushrods installed. On a cylinder without pushrods the input valve will be held closed by the air pressure.

This manifold is a temporary fixture; I hope to incorporate a better design into the final design of a stand and base.

We are going offroading tomorrow (snow possible ::)), so if I don't break anything on the Jeep I might be able to make some more progress on the engine.
Title: Re: Another Halo
Post by: NickG on December 05, 2009, 06:41:47 AM: Very nice work Kirk, can't wait to hear this beauty 'fire' up!

Nick
Title: Re: Another Halo
Post by: kvom on December 08, 2009, 07:21:41 PM: Despite a list of things I "should" be doing, I spent most of the afternoon doing some fit and assembly of the heads to the cylinders. For any interested onlookers, here's the procedure (just repeat 5 times).

First, place the valve balls into the input (left) and output valve bores.

(http://www.pbase.com/kvom/image/120128502/medium.jpg)

I found it tricky to get the depth correct, so before further assembly I tested each visually by pushing the plunger while looking to see that the ball moves upward. If not, the bore is not deep enough. Using a depth mic, I determined how much more was needed to reach the indicated .185". Then I chucked the head in the vise and used a #8 reamer in the mill to deepen it. Mostly I needed around .005" or so.

Next, fasten the valve cover to the head, making sure that the inlet hole is on the left.

(http://www.pbase.com/kvom/image/120128503/medium.jpg)

Next the head must be attached to the cylinder. Note that one hole is counterbored do allow the rocker bracket to sit flat. For this reason the bracket is attached after the head.

The plungers are now inserted along with their springs. I cut down the springs to 3 turns to reduce the force on the cams. We'll see if it need more or less when we try to get it to run.

(http://www.pbase.com/kvom/image/120128505/medium.jpg)

Finally the rocker bracket and arms are attached.

(http://www.pbase.com/kvom/image/120128506/medium.jpg)

With all 5 heads assembled, we have this front view:

(http://www.pbase.com/kvom/image/120128507/large.jpg)

And from the rear:

(http://www.pbase.com/kvom/image/120128508/large.jpg)

I need to get some more plastic tubing to attach my little manifold, and then cut the pushrods to length before the first trial with air.
Title: Re: Another Halo
Post by: Darren on December 08, 2009, 08:46:05 PM: You have come on well with this, doesn't it look quite something .... you excited yet :)
Title: Re: Another Halo
Post by: chuck foster on December 08, 2009, 09:29:29 PM: what a build :bugeye: i bet you can't wait to see this one run.............heck i didn't build it and i can't wait to see it run :D

it has been a big project and i just want to say thanks for the pictures and the write up :ddb: :ddb: :ddb:

chuck :wave:
Title: Re: Another Halo
Post by: NickG on December 09, 2009, 03:37:14 AM: Brilliant Kirk. :ddb: I wonder if they had so many spring coils to avoid valve bounce? but I would have thought that would only happen at stupid speeds.

Nick
Title: Re: Another Halo
Post by: kvom on December 09, 2009, 08:25:33 AM: The pictures on Liney's suite show only about 3 coils. When I first tried a single assembly with 5 coils or so, the force on the cam was significant. I'm concerned that I might need to file the leading edge of the cam surface to make the "entry" easier. Of course that would mean a complete disassembly. :scratch:

My other pre-run concern is whether the valve balls will seat properly and seal the valve passage completely. It's rather difficult to lap the valve seats when they are so small. The prototype uses brass for the heads, and I suspect that brass would yield a cleaner surface for the seats. We shall see.

After putting this together with a couple of hundred 2-56 SHCS, I'd suggest to future builders to invest in a t-handle 5/64 ball-end allen wrench vs. the standard L-shape.
Title: Re: Another Halo - first air
Post by: kvom on December 09, 2009, 04:06:01 PM: This afternoon I hooked the manifold to the engine and applied 5 PSI air. As I feared, there is significant leakage around the input valve seats. Of 5 heads, only one seals completely. Three others have smaller leaks (e.g., when I push in the plunger the airflow increases significantly). The last head seems not to seal whatever.

What I should have done, prior to assembly, is test each head's valves. If I insert the balls and apply air, then no air should escape. Similarly, I can turn the valve cover around so that the input barb is over the output valve and test it in the same way. In testing the output, air will still flow out the bottom, but not from the side exhaust hole. Blocking the bottom hole should result in no air flow at all.

So I have made a simple manifold with just one output barb that should make this testing easier. However, when I discover which valves are defective, I'm not too sure I'll be able to fix them.

For other builders, this testing might be appropriate while partially machining the heads. If you drill/ream the plunger holes, drill the valve holes, and drill/tap the valve cover holes, the valves can be tested before doing the rest of the machining of the heads. Just an idea. If I have to remake the heads I will likely test them this way.
Title: Re: Another Halo
Post by: NickG on December 09, 2009, 06:08:11 PM: Kirk, keep at it, there's always a bit of trouble shooting esp on one this complex you'll get there. Is there nothing you can put in there to seal the valve seats?

Nick
Title: Re: Another Halo
Post by: chuck foster on December 09, 2009, 08:19:48 PM: just a thought..............what about using a small brass punch and hammer.
put the ball's in place (on there seats) put the punch on top of the ball and tap it lightly with a small hammer.
this may peen the ball into the seat and it just might cure the leak's.

chuck :wave:
Title: Re: Another Halo
Post by: kvom on December 09, 2009, 09:04:03 PM: That's a good suggestion, Chuck. I'll try that next shop session.

After dinner, I did a test on the one "good" head, as I described above. The seal is not perfect, as there's a very slight leak on both balls. When I activate the plungers, there is a very good air flow, so I think this one might work. I decided to reassemble the engine with just this head, add the pushrods, and see if I can get it to run on one cylinder. In a moment of absentmindedness, I dropped the brass couplers into the cam housing without inserting the balls first. :hammer: Then it was a royal PITA to get them out, a process which resulted in one of them flying off the workbench and into oblivion. So unless it shows itself there's at least one part to remake. Guess the lesson is don't work in the shop at the end of the day when you're a bit tired.
Title: Re: Another Halo
Post by: cedge on December 09, 2009, 11:34:28 PM: Kirk
Tapping a valve ball into its seat is a common practice in hydraulics. One sharp strike will usually deform the edge of the seat to fit the ball, giving a nice full contact fit and seal. I've fixed many an old valve that way rather than charging a customer for a whole new valve.

Steve
Title: Re: Another Halo
Post by: ariz on December 10, 2009, 04:38:57 PM: kvom you're really near the end of this complex build
concentrate yourself, don't work whem tired :hammer: and solve the last problems
we want see this beautiful engine running, and surely it'll run :thumbup:
Title: Re: Another Halo
Post by: kvom on December 10, 2009, 06:47:54 PM: Thanks to a suggestion to seat the balls in the valve bores (from Cedge and Chuck Foster, thanks guys :thumbup:) by tapping them in with a drift and a hammer, I think I can get the valves to work. I did the first 4 before it was time for dinner and a rest. The seating isn't absolutely perfect in all of them, but hopefully good enough.

I did find a few things for other builders to watch out for. First, the hole for the inlet barb isn't completely over the inlet valve bore, and the threaded portion of the barb is thicker than the valve cover. So when I tightened the barb I got leaks between the cover and the head. So when seating the balls I also gave the inside surfaces a rub with 360 sandpaper and Scotchbrite.

I was also finding a fair amount of small swarf, including some round "wires" that seem to result from the drilling/reaming process. I made sure to pick these out with tweezers and also to blow air through all the passages. I think the wires are burrs created when drilling/reaming the holes for the plungers. I drilled these holes first and the valve bores last, but perhaps the order should be reversed.
Title: Re: Another Halo
Post by: kvom on December 12, 2009, 08:51:03 PM: There are two sizes of balls used. The 3/16" for the valves, and 1/8" balls for the rod lifters. These small balls ride on the cam surfaces; the rod plungers sit on top of these; the pushrods connect the plungers to the rocker arms.

Rather than any assembly drawings, Liney provides a set of transparent sheets with various assemblies drawn to scale. By putting these on top of each other you get an idea of how the parts interact.

Today I spent a couple of hours in the shop. The first order of business was to make a new "flywheel", as the one I made from the end of an axle shaft was too hard to tap for a set screw. I made the one in the photo from a scrap piece of hex 12L14 steel. I drilled the cross hole 1/8", then counterbored with a #7 drill and tapped for the 1/4-20 screw. There are 3 #4 lead shot between the engine shaft and the set screw.

(http://www.pbase.com/kvom/image/120226085/medium.jpg)

After finishing seating the valves in the last head, I worked a bit on the pushrods. These are simply 1.4" lengths of 1/16" drill rod. I cut them a bit long with a wire cutter, then filed both ends flat and to length. However, my first fitting showed them to be a bit short. So now it seems that either I need to have longer rods, or else the valve plungers need to extend higher from the heads. The latter means that the springs may need to be longer.

From the plans, the cams have a radius difference of only .05" between the open and closed valve positions. This means that the plungers will only move .05" to open the valves. Somy next shop session goal will be to determine where then plungers need to be in the closed position, and adjust to suit.
Title: Re: Another Halo
Post by: kvom on December 14, 2009, 02:16:55 PM: Did a couple of small tasks on the engine:

First I remade the crank pin a bit longer so that I could tighten the screw without binding the piston rods. There is really no reason that it can't be longer than the plan's dimension.

I "discovered" that I had failed to machine the pocket in the head that I was test fitting the pushrods on. That meant that the rocker and its arms were .05" too high. Hopefully the next time I put it together things will fit better.

As far as I can tell, I have everything set to try a test run the next time I get into the shop.
Title: Re: Another Halo
Post by: kvom on December 17, 2009, 04:15:22 PM: I did the recommended tuning and adjustments as recommended by Liney for the first cylinder, and after some fiddling got a runner. Here's the evidence:

http://www.youtube.com/watch?v=IvhgMdTBUYM

To get enough flywheel weight I clamped my tapping station chuck onto the shaft. On the video, I started it at 40 PSI and gradually reduced the pressure to 20 PSI at which point it stops. With more cylinders and some run-in I expect it will run at a fairly low pressure. For other builders I will reiterate the setup process and some issues I encountered.

My first "concern" was realizing that the pushrod holes in the cam housing are not centered on the cylinder. It seems that my setup on the rotab was a bit off. While the drawings from Liney show the pushrod for the inlet valve connected to the rear hole, I decided to reverse this to make the rods more upright. Since the cams are symmetric, this isn't a problem as long as all cylinders are set the same.

The first adjustment is to set the crank pin/conrods relative to the cams. This is the sole timing adjustment and is needed only for the first cylinder. I slightly loosened the screw that holds the crank to the shaft and then turned the shaft until I felt the inlet cam contact the ball bearing that pushes the inlet rod. Holding the shaft steady, I pushed on the crankpin so that the piston was at TDC (i.e., you want the inlet valve to start to open at TDC). Now it's time to tighten the crank to the shaft; however, the conrod blocks access to the screw head, so I needed to slowly rotate the shaft and crankpin together until I could get to the screw with a small screwdriver. It's for this reason that you need some friction with the screw initially: loose enough to be able to adjust the crank pin but tight enough so that the pin turns with the shaft. Note that I set it up so that the engine turns CCW as seen from the front; to reverse this direction turn the crank pin 180 degrees relative to the cam.

Next, the travel of the rocker arms needs to be adjusted. Connect air at low pressure and turn the shaft until the inlet valve is open. Then adjust the outlet rocker via the SHCS until air is coming out of the exhaust. Next back it off until no air is exhausting. The exhaust pushrod length is now set. Now you can lock the adjustment screw with a 2-56 jam nut. The small issue I had with this is that the screws supplied may not be long enough to protrude out the top of the rocker. For this reason, I plan to use longer screws on the other cylinders and cut off any excess once the jam nuts are in place. A 3/16" nut driver is an excellent tool for tightening these small nuts.

The same procedure is followed for the other pushrod. Turn the crank so that the exhaust is open and adjust the inlet pushrod until air enters the inlet valve; then back off and lock the jam nut.
Title: Re: Another Halo
Post by: Bernd on December 17, 2009, 04:18:29 PM: ALL RIGHT Kirk. :bugeye: :thumbup: :beer: :bow: :ddb: :nrocks:

Lookin' good.

Bernd
Title: Re: Another Halo
Post by: NickG on December 19, 2009, 09:36:04 AM: Wow Kirk, looking very good. How far away are you from a run with all cylinders? It sounds fantastic even with just one!

Nick
Title: Re: Another Halo
Post by: kvom on December 19, 2009, 01:13:09 PM: My first 5-cylinder trial was not a success. :scratch:

First I had to remake the skewed rocker arm, and the blank I had left over from the first batch was too thin. So I spent probably an hour making one from a bit of 1/4" thick aluminum. Note to self: finally buy a set of thin parallels.

Once assembled, the last head seemed pretty leaky on the output valve, but I decided to hook it up anyway. Applied air up to 60 PSI without a runner. Then I noticed that the crank had become loosened from the shaft so that it wasn't turning. By then it was to late to pursue a readjustment.

With all cylinders attached, there is a fair amount of force needed to turn the shaft by hand.
Title: Re: Another Halo
Post by: kvom on December 30, 2009, 02:12:11 PM: I decided to make the hose barbs myself using some .25" brass round. Nothing too complicated other than some tedious tool changes on the lathe. Outer barb diameter is 3/16", with the inner diameter 1/8" and the air passage 1/16". I then drilled the mounting holes in the manifold cover, reamed oversize, and fixed the barbs with red loctite. The inlet barb I just cut from a store-bought connector and loctited to the body of the manifold.

(http://www.pbase.com/kvom/image/120681573/medium.jpg)

With the loctite cured overnight, I assembled to the mount and crankcase.

(http://www.pbase.com/kvom/image/120681574/medium.jpg)

Then it was time to connect some platic tubing.

(http://www.pbase.com/kvom/image/120681575/medium.jpg)

I gave the moving parts a dose of oil and hooked up the air. Unfortunately things went less well from there. It turns out that the inside seal between the manifold cover and body isn't airtight, and all the air is exiting there rather than going to the cylinders. So my plan is to make a gasket from oiled kraft paper, as shown on a recent thread.

As I was disassembling the manifold from the engine, I noticed that it wasn't screwed tight. So now it seems that the mounting screws are several threads too long, meaning that the cover was not cinched down tightly to the body. Rather than cut the screws down, I'm still going to make the gasket first.

While everything was assembled, I did a few minutes run-in with the electric drill, and the mechanism doses seem to be turning with less force. I may attach it to the mill spindle and let it turn at low speed for a longer period while the gasket making gets underway.
Title: Re: Another Halo
Post by: kvom on December 30, 2009, 05:00:31 PM: We have a runner. :med: That is all.

:worthless:

Film at 11 (or when my daughter tells me where she hid the camera)
Title: Re: Another Halo
Post by: kvom on December 30, 2009, 08:50:21 PM: After the early afternoon trial, I made a paper gasket and oiled it to try to seal the manifold. I still needed to shorten the screws to get everything tight. I also hooked the shaft to the mill and ran it for about 30 minutes at ~300 rpm. At the end, the mechanism was slightly less tight.

I then needed to readjust the timing. The connection of the crank to the shaft is by a single flat-head screw. If the engine is turned the wrong way, the screw will loosen and the crank will not be turning. So it is important that the engine only turn clockwise as viewed from the front.

I also adjusted the timing so that the piston is slightly past TDC when the inlet valve opens.

Once all this was done I reattached the air and started to turn the engine by hand via the attached chuck. I started to feel a bit of a kick, and then it sprang to life. The manifold is still leaky, but not as badly as before so that the cylinders are getting air. I imagine that with a better sealed air supply it should run at lower supply pressure.
Title: Re: Another Halo
Post by: Powder Keg on December 30, 2009, 09:49:19 PM: Those sound awesome!!! Great job!!!
Title: Re: Another Halo
Post by: sbwhart on December 31, 2009, 03:59:16 AM: Well done great Job :clap: :clap: :clap: :clap: :clap:

enjoyed the build

Stew
Title: Re: Another Halo
Post by: Darren on December 31, 2009, 08:41:10 AM: Simply brilliant :bow: :bow: :bow:
Title: Re: Another Halo
Post by: Bernd on December 31, 2009, 12:21:53 PM: Finally a runner all right Kirk. :thumbup:

You deserve a few of these :ddb: :ddb: :ddb: :ddb:

I'm sure once it's run for a while the engine will take less pressure.

Bernd
Title: Re: Another Halo
Post by: NickG on December 31, 2009, 12:28:07 PM: Nice 1 kirk, a brilliant project and brilliant result! you must be chuffed.

Nick
Title: Re: Another Halo
Post by: kvom on January 01, 2010, 05:58:17 PM: I spent the afternoon rethinking and then remaking the manifold. Here's the result:

(http://www.pbase.com/kvom/image/120730314/medium.jpg)

The body, made of 12L14 steel is actually two pieces. The first piece I turned as a disk 2.000" in diameter, .5" thick, and bored out to 1.250". I then used a grooving/cutoff tool to turn a groove into the outside .25" wide and .35" deep to provide the air channel. The second piece I turned 2.25" in diameter and bored .199. I then pressed piece one into the bore of piece two. Then it was off to the rotab to drill the mounting holes and holes for the air barbs.

I mounted it to the engine, and while it's not 100% airtight at the pressed seam, it's a lot better then before.

Unfortunately, the engine then decided not to cooperate by running at any pressure. Seems the crank screw had loosened up again. Arghh!

So next shop session I'll adjust the timing again and tighten the screw. I also want to check all the valve again as I didn't seem to feel proper airflow from every exhaust port.
Title: Re: Another Halo
Post by: kvom on January 02, 2010, 04:10:43 PM: I spent a while in the shop this afternoon getting a start on the base.

(http://www.pbase.com/kvom/image/120756758/large.jpg)

One lesson learned was that when cutting a deep slot with a small endmill, clearing the swarf as it cuts is a good idea. Cost me a 3/16" carbide endmill to learn this.
Title: Re: Another Halo
Post by: Bernd on January 02, 2010, 06:02:53 PM: Kirk,

That engines starting to look real good. A bit of polish after you get it all straightened out and you got a winner. :thumbup:

Bernd
Title: Re: Another Halo
Post by: Powder Keg on January 08, 2010, 09:43:01 PM: How's your engine coming? I sure like the way it sounds.
Title: Re: Another Halo
Post by: kvom on January 09, 2010, 08:50:21 AM: I did get it "finished", although in the first test run the crank pin came loose. I was running it in the wriong direction. Since it needs partial disassembly to be put back together and retuned to turn in the correct direction, I decided to do the bling polishing while it's apart.

Learning polishing now, with the beam engine as my first target.