Modified Rocking Engine

[NickG]

Hi all,

Tonight I started machining the components for my Rocking Engine so am going to do a bit of a project log here.

Incase people haven't seen the design thread I did, basically, I was messing around with the Alibre CAD software I bought for $99, which incidentally was a bargain, and it spawned this:





Anyway, I wasn't sure whether I'd make it as the design is a bit OTT for what it is, was only messing around with the CAD really, but a few of the guys on here convinced me to give it a go. So I completed the drawings over the weekend and also got my garage / workshop sorted out. Just moved house a couple of months ago so it was in a state of turmoil!

Not a great deal to show you after the first night's work I'm afraid! Before I started, I remembered something Stew had said, that while you've got everything set up, and your head around making a component, it's often as easy to make two! That makes sense and it'd be nice to have 2 completed engines.

I started on the pedestals, there are 3 of those so I was going to make 6! Because of this, I thought I'd be clever and set up some calipers and depth gauges etc to make it a speedier process.





I found some 1/2" stainless steel bar which was machining nicely, but then I realised I'd already made a boo boo! I'd gone in with a sharp tool not allowing for the radius. So I tried to grind a tool with a rad on it, just by eye. All I would have to do was machine a bit further along the bar to sort it out, but the rad tool gave a shocking surface finish, so I ended up putting the larger rad in with a needle file! I managed to grind a tool which gave a decent finish for the smaller rad  on the centre section. It's not perfect but it's that small you can hardly tell to be honest. The only other thing I did was made the bottom thread for fixing to the base 2 BA instead of 3/16" x 40 TPI. I think I probably have some 2 BA nuts kicking around, I don't know why I went for the ME thread in the first place really, it's not necessary.

After 2 hours work this is all I have to show:



After all that tool swapping and cutting threads it tells me that I could really do with a QCTP and a tailstock die holder.

I've abandoned the doing 2 of everything now, if this took me 2 hours it's going to be circa 26 hours for the complete engine, so I think doing 2 of everything is just going to annoy me, although I still think it’s a good idea in principle!

That’s all for now anyway, feeling slightly disheartened due to slow progress but hopefully it’ll pick up!

Nick

[chuck foster]

looking good nick 

keep us posted.

chuck

[sbwhart]

Hi Nick

Nice start  , it only pays doing multiples if you got the tools to take advantage of it :- QCTP, Tap and die tail stock holder, back stop, collets, vice stop:- etc etc.

Just a few more jobs to add to the list  

Have fun

Stew

[raynerd]

Hi Nick

Excellent work - it is really great seeing your design and then you going the step further into making it.

I have just purchased Alibre and have to say that I`m struggling a bit with its use. I have followed a few "step by step" tutorials but then it all fails when the tutorial shows X thing happening and on my screen Y happens! Anyway, I`m sure I`ll get use to it! Quick question in reference to your plans, does alibre allow you to not only model the 3D design but then revert back to 2D to attain plans such as those you are working from - i.e standard CAD style plans?

Chris

EDIT: PS. after the few models that I have made, I now appreciate even more the need for the correct tooling. I think 50% of my time is taken measuring up, 20% finding my damn tool in the first instance, 20% swapping tools and the rest doing the job. I think a QCTP will reduce to tool swapping and finding and after my mill X axis power feed that I am working on, it is my next project before I go any further.

[arnoldb]

Good start Nick 

Looking forward to the rest 

[NickG]

Thanks for the replies guys! Feeling a bit more up beat this morning, there are 12 components left, but some aren't as fiddley as that one, so if I get my finger out, I could do it in a week I think! Beware though, i've made these sorts of bold claims in the past and a month later I'm still applying finishing touches!

Chris,

With regards to Alibre, the way 3-D CAD systems work is that you create all of the geometry from 3D building blocks as it were stuck together to form 1 part. From that, the computer can generate / project the 2D geometry by just looking at it from different view points. That's all you do when you create the 2D drawing. It asks what views you want and you just place them on a sheet of paper. If you have your preferences set right it'll automatically dimension it for you, however, I'm not a fan of that, it sometimes jumbles them up and doesn't necessarily put the dimensions on that you or I would knowing we have to make it next! Then you can do other things like sectioned views and detailed views where you blow a small feature of a part up to a larger scale for clarity. Once you have the 3D model and 2D drawing they're linked. If you update the model and save it, the drawing automatically updates. Similarly, with the assembly, which is a file with all the parts mated together, this will update if you update any individual part.
With the assembly you can mate parts with the correct constraints they would have in real life, therefore giving it the degrees of freedom it would have in real life which means you can grab the flywheel and spin it over! Unfortunately this version of Alibre doesn't have the animation add on which is an extra so you can't get it to do it automatically. Keep going with it, you'll love it. It takes a bit of practice, I've used various 3D CAD systems for years and they all work in a similar way, think that's why I picked Alibre up so quickly, have to say it's the most intuitive one of the lot.

With regards to your comment about tooling, that is spot on, that's exactly what happened to me last night!

Keep watching and I will post regular updates!

Cheers,

Nick

[NickG]

Hi all,

got a little bit more done but am afraid this thing is going to take longer than I thought, probably 2 or 3 weeks!

After doing that little pedestal I couldn't face doing another 2 yet ... bored of that! (No patience!) So, I decied to do the cylinder and cover. I'd been mulling it over in my head overnight and thought that if I get the cylinder done except the bolt holes, then the cyl cover finished, I could transfer the holes from that into both ends of the cylinder and the frame when that's done. Then everything will definitely line up.

Unfortunately after 3 hours in the workshop I cam out with no finished components! 

I've got the cylinder and cover part done, just need holes drilling in cover, transferring to cylinder then those tapping 8ba.

I made a bit of a mistake on the cylinder which is annoying as there couldn't really be a simpler component! I didn't bore it out quite long enough ... thought I had allowed a good 1/8" extra when I drilled it, but I must have stopped boring short of the drilled hole. This was probably due to boring a blind hole ... at least I can learn a lesson from this, bore it right through. Anyway, this has resulted in the cylinder being 1/16" shorter than it should be. So I'll need to change the drawings, I'll need to make the crank throw shorter and move the bearing hole further away!  I was going to use an adjustable reamer I'd found to finish the bore, but I found the surface finish from boring good enough. Just as well because for the adjustable reamer I'd need to have bored right through anyway. I found a nice piece of phosphor bronze for the cylinder.

I originally called for steel for the cyl. cover, but saw a bit of that nice aluminium so used that instead. Pretty simple turning job. I always used to find it difficult turning little registers for a good fit in the bore but on this lathe I seem to be able to get it spot on. The sali machines really well and I parted it off with on the slowest none back gear speed and the slowest cross feed. Worked superbly. Had to put back in the chuck to finish the outside  so put a bit of aluminium from some old vanishen blinds around it to protect it from chuck jaws, nipped the jaws and used the tailstock chuck to push it to run truew whilst rotating at slow speed.

Apart from the silly mistakes i keep making it's going quite well. Still frustrated by how long it takes to change lathe tooling etc though. What I am happy with is the surface finish I'm getting. If I keep this up, I prob won't be trying to bling anything, just a quick polish with a rag and some silvo to keep the dirt away, or eve just with oil and abit of wire wool. I really need to get a polishing attachment for the grinder if I want to bling stuff.

Anyway, here are the part finished parts! Look a lot better in real life, camera never does stuff justice!



Nick

[Brass_Machine]

It is a neat thing to see an engine (or whatever) go from design to build!

Way to go Nick!


Eric

[NickG]

This is going slowly! I need 

All I got done today was finish the cylinder and cover.

I put the cover in the lathe and made it run true the same way as I did before, brought the tailstock up to it whilst nipped in chuck and running slowly.

I marked the positions of the 6 holes by lightly scoring a circle of the right dia. with the cutting tool on the inside face, then indexed using the 3 jaws of the chuck and a small spirit level on each jaw getting them as near as I could to horizontal each time and scoring across the circle with the cutting tool.

Centre drilled and drilled through, it's tough stuff this aluminium though, made me realise both my no 50 drills were blunt so had to go through with 52 first.

I then put the cover on the cylinder and spotted through the holes on both ends. The 6 divisions are good enough not to be able to notice by eye but they won't line up in any position, only 1! I need a rotary table with compatibility to lathe chuck but this will do the job, so long as I spot the frame holes with the cover too.

I opened up the holes to 8 BA tapping size in the cylinder and started tapping the holes. Used a taper tap in the drilling machine to get them square then thought i'd just do it by hand with the plug tap so I could get more feel.

All was going well and I was just thinking to myself, I used to break taps like this .. I was so careless back in those days, am much better now. 10 mins later this thought came back and bit me in the @rse and the tap snapped!  Think my taps were pretty blunt. Without thinking I tried to get it out using a centre punch, which didn't work, just made a few scratches on the end face of the cylinder and a bit that pinged off hit me in the cheek. Could have been nasty if it were a bit higher, I wouldn't care, I'd had my glasses on 90% of the time too. Always wear safety glasses.

After conceeding I wouldn't get it out I thought well, I don't really need to. Luckily it was in the end that bolts to the frame, so all I'll have to do is tap that hole in the frame and put a dummy bolt in instead of drilling clearance size. 5 bolts are more than enough to hold it.

Here are a couple of pics. First of the frame end with the broken tap.   





No one will be able to tell once it's together. Hopefully no more mistkaes!

On another safety note,  does anybody wear gloves whilst they're in the shop? I know there are other hazards associated with gloves and machinery but I'm for ever getting little shards of metal stuck in my hands which can be painful and difficult to get out. How do people avoid this ...guess never touching swarf with bare hands would be a good start but I can't seem to avoid it.

Nick

[raynerd]

Looks good to me !! 

[bogstandard]

Nick,

As you know, gloves are a definite no-no when working on moving machinery, but for picking up swarf they are a must. I use the very thin woven cloth ones that have like a layer of some rubbery solution on the fingers and palms.

I usually use a small rake when moving curly swarf about, and for brass needles it is the vacuum that is the only safe way, NOT by blowing it away with an airline. That is like sewing a mini skin minefield all over your shop and machinery.

I don't think you will ever get over the skin penetration problem of brass, in fact I got one the other evening on an inside thumb joint, but didn't notice it because it was so small. The next morning when I woke up, it was all pain and puss which required microscopic surgery on my part. I have just felt something in the bottom of my foot, so I will get the wife to do the necessary on that.

A good barrier cream does help in keeping the instant infection down, but as you can see, it still got me.

I suppose surgical gloves would be OK, but from experience, any more than half an hour is too long for me, even though you don't realise it, your hands sweat profusely, and they soon become very uncomfortable. I tend to use the blue vinyl ones rather than latex, I find them much stronger and able to cope better with the rigours of the workshop.


John

[NickG]

Thanks John,

The one on the thumb joint sounds painful!

I've tried surgical gloves but find they tear pretty easily with the sort of stuff we do. Although we use some green ones for work, can't remember what the material is called, they are a bit tougher, might try those. Keep your hands clean too. I still don't like wearing them really though, even though they are thin, you don't get the same dexterity.

Going to try to get in the shop every night this week as I'm away a 3 nights next week.

Will probably go for the frame next.

Nick

[NickG]

Not a great deal to show tonight! Just some straight forward milling for the aluminium frame.

Can't remember whether I mentioned, when I moved into the new garage, er I mean house  there were some shelves that needed to come down. The brackets were over a foot long and bend from 3/8" x 1 1/4" aluminium bar! Thought that would come in handy!

Anyway, I didn't actually know it was 1 1/4" wide until tonight, which was handy as that is how wide I designed my frame ... good guess!

Cut out a lump long enough for both parts so that i could machine it down to size, as I said, didn't need to touch the width, so just milled both ends square. I found I had to climb mill to get a decent finish, the alloy must be very soft and it was picking up all the swarf if I didn't climb mill.



The bar was slightly over 3/8" but didn't correlate to any particular metric size either! So took 60 thou off each side. The quill DRO was really handy here, wish I had a full proper dro on both machines, would be superb!



Got a pretty good smooth finish and that's with an old 5/8" slot drill. I used that because it's how I'm going to cut the hole to match the cylinder bore in the square piece, however, I need to change the cutter anyway to cut the rads on the corners so it was floored logic! I should have tried  one of my cheap chinese brand new cutters on this soft stuff, would prob get a good finish whacking the speed up with a new cutter.

Here's the bit of metal



Hacksawed it in 2 and put both pieces back in the milling vice.



Finished the sawed ends to length. Milled to marked lines by eye then measured and I still needed to take another 10 thou off both times. Did this with the hand wheels, they aren't that accurate but it's only about 2 thou over size ... good enough.



Left it at that tongiht and quite while I was ahead! Or at least not made any mistakes! I was going to leave that set up and basically finish using the handwheels but I think I better take them out and mark up as a check. Might even use marking blue - any tips on that? I've never really used the stuff before, not sure on the techniques!

BY this time tomorrow I should (touch wood) have those 2 frame pieces done and a part assembly that should start to resemble an engine of sorts!

Nick

[sbwhart]

Hi Nick

Nice work    I usually put marking blue on with a soft brush leave it for 10 - 15 min to hardeb off.

Next time your at RG ask the guys on engineering if they can get you some "Showa" gloves, their cotton coated with some durable rubber especially developed to prevent cuts, better still give them a ring and get them to post you some up.

The big problem with surgical gloves is your hands start smelling like feat 

Have fun

Stew

[NickG]

Stew, will give it a go. How do you get the stuff back off? With emery cloth? Although these bits have a really smooth finish you can still see lots of machining marks from the end mill so think I might give them a rub on emery to get rid of that. Might look a bit un finished if it's got all those swirl marks on it.

Will make some enquiries about the gloves!

Having fun so far! I think the problem I might get with this ali frame is cutting threads. It seems really soft stuff. 5 threads to cut, is there any kind of lubericant you can use to imrpove this? Paraffin?

Nick

[sbwhart]

Hi Nick

Meths, Turps or just a squirt of WD40 will get it off.

Have fun

Stew

[NickG]

Cheers Stew 

[No1_sonuk]

Stew, will give it a go. How do you get the stuff back off? With emery cloth?

If you mean the marking blue, I use IsoPropyl Alcohol ( IPA ).  You can get it from Maplin in a spray can. 

http://www.maplin.co.uk/Module.aspx?ModuleNo=28994

You won't need much - even the small can will go a long way.

Spray on and wipe off with tissue, paper towel, etc.  Also works spraying some on the tissue, then wiping.
You can also use it to "re-wet" the blue that hardens on the brush.

Emery cloth will mark the surface. IPA and tissue won't. 

IPA will also remove "Sharpie" ink...

[Bluechip]

Well No1_sonuk  .. you must be flush with cash to use Maplin £7.49 for 400ml  

Little wonder they have it 'in stock', as far as I'm concerned, they can keep it there.

http://www.rapidonline.com/Tools-Fasteners-Production-Equipment/Service-Aids/Cleansers-Solvents/Isopropyl-IPA-cleaning-solvent/61590

Or a bit less from above.. needs 15% vat on it tho .. P&P requirements about same

As an aside, knowing their prices, do anyone use Maplin now? I stopped about 12 yrs ago.

Dave BC

[NickG]

Dave,

  I occasionally use maplin for bits and pieces. Just because they have a shop you can go into, and for resisters and stuff it makes little difference whether it's 3 p or 30p if you're just getting 1 or 2! The last things I got were a few ceramic resisters to replace the wire wound ones in the wifes heater fan controls. Also, I bought a timer circuit kit for about £8 which I wired through relays and all the rest of it to keep the anti perc fan switched on for a set time after I switched engine off on Renault 5 turbo! It worked a treat and it was great fun soldering the circuit together and getting it to work .. took me back to my youth!

I know what you mean though, my dad used to be a technology teacher and they always used rapid electronics. Remember one of my christmas presents about 15 years ago when I was 14 was one of those sets of little drawers full of electronic components from Rapid electronics along with a few bits of strip board! Was one of the best presents ever! Still got most of it in the same little drawers! Had a few hobbies down the years!

Nick

[No1_sonuk]

I only suggested Maplin as it's easier to get at.  Industrial supply places would be cheaper.
I bought mine soooo long ago, I can't remember where it came from.
It really doesn't take much.

  I usually use Rapid, CPC, or Farnell for my parts requirements. Maplin ceased being little more than a high-tech toy shop several years ago.  Shades of the "What will happen" thread...

[NickG]

  Very true! Forgot I bought an electric trike for my 3 year old from there too! Those things were several hundred pounds when I was a nipper ... £29.99!

Nick

[NickG]

Hi all, unfortunately I didn’t get done what I planned tonight. I could have stayed out longer but when it got to 10:15 ish I was getting a little tired and had enough really.
Basically, I got the hole drilled in the cylinder support part of the frame, the rad cut on the corner and the ring of bolt holes to fasten the cylinder on. Still need to drill and tap the holes that will fasten it to the other part of the frame that supports the bearing and the hole for the pedestal to stand it on.
I blued the bits up then forgot to mark them out! So thought sod it and just used the hand wheels to position the hole! I worked out how far in graduations it took from one side to the other though then split it, since I know my hand wheels aren’t very accurate.

Drilling the big 5/8” hole with the slot drill.


Drilling the rad with the ½” slot drill.


Copying the holes from the cylinder cover to the frame. Note  bottom hole was only spotted, this needed to be tapped 8ba in frame for dummy screw to account for snapped tap in cylinder!


Tapping hole for dummy screw


Progress so far


Not going as fast as I would have liked, but I’ll get there!

Nick

[sbwhart]

Coming along nicely Nick 

Have fun

Stew

[Stilldrillin]

That`s looking good Nick! 

David D