Elmers VR75 build log

[spuddevans]

So I've got the workshop into a place that I can now start to use it for the intended purpose, and I also have got my 1st project done ( A custom titanium ring for my better half. Bribery if ever I saw it  ) so it is on to making another little engine, and wanting to do something different but not too difficult, I settled on Elmers VR75.

This is a slide valve engine which I've not tried to build before, and it has reversing gear which also interests me and looks nice too.

Before I start I have to apologise to anyone who has a slow interweb connection, as I am firmly a believer in  and so will be taking loads of pictures of all stages of the process. This may be really boring for some, but I like seeing others machining setups and how they do things, so hopefully someone may find some of my pics interesting 


So after downloading the plans from John-Tom I set about studying them, and like all other of Elmer's plans they are in fractional inches. Many are very comfortable using imperial measurements, but I am not among them. Added to that I haven't built up much of a stash of metal stock, so I decided to make the conversion easy for myself by scaling the plans 16mm to the inch, ie 1/16th" = 1mm.


So now that we've got that epic tome out of the way, on to the build log.


I started out by making a crude sketch on the whiteboard (one of the most useful purchases in my workshop) of the Engine base with scaled metric dimensions.




Then I found a piece of 10mm thick ali plate and stuck it in the bandsaw to trim it to slightly oversize. However I had not checked the bandsaw and it was not cutting straight, fortunately I caught it in time.

Then, because one edge was good, I put the good edge to the bottom of the vice on the mill and clamped it up. I also stuck a 16mm endmill in the chuck. As you can see below, when I put an endmill into the chuck I try to always have a bit of wood or a cloth directly below it, you only have to drop it once to increase your collection of blunt endmills




You may also notice that I put the Ali over to one side in the vice, the reason for this is illustrated below



It saves taking the workpiece out of the vice to measure it. But I think that if the workpiece does not reach past the centre of the vice, then you need to put a packing piece on the other side that is the same thickness to keep the clamping pressure of the vice even.

Then after reaching 44mm, I placed the Ali Base on some parallels in order to square the ends and complete the sizing.




I've found that when milling edges like this, especially on aluminium, it is helpful (if you have a free hand) to gently hold a paintbrush against the endmill, it helps clear the chips to stop them clogging the cutter.




This pic shows what happens when I don't. The brush was held against the endmill for the 1st little bit, then taken away for the rest.




Anyway, after measuring and milling, I ended up with this block 64mm x 44mm x 10mm (I don't know whether to thin it down or not  )




So that was as far as I got before the call of the wild (Food), stay tuned for irregular updates

Next up will be drilling all the corners out and also drilling some holes before milling out the cut-outs.

Tim (glad to be back in the saddle workshop again)

[dsquire]

Tim

Good to see you making the chips fly instead of the sawdust. You sound like your having fun. 

Cheers 

Don

[spuddevans]

Thanks Don I really am having a lot of fun getting used to using my machines again.


Ok, so today's seen a bit more progress on the base.

I started off by blacking up the base and then marking out the places for all the holes. Not strictly necessary as I was going to machine it using the DRO's, but it I find it to be reassuring to see that the holes are being installed in the right places.




Then I mounted the base on parallels in the vice, and then used an edge finder to zero the DRO's in the bottom left corner. Then I can reference all operations from that point.

Then I chucked a centre drill in the chuck and then went to each of the co-ordinates and spotted them.




Then I did the same thing again with a 2mm drill bit. Then I worked out the corner points of all the cutouts and centre drilled and then drilled through 4mm.

Then I started to mill out the cutouts. I started with a 4mm endmill but found it was taking it forever, as I was only able to take 0.8mm depth of cut per pass. After milling out 2 of the cutouts this way, inspiration struck ( or was it a particularly sneaky attack of wind ?  ) and I remembered I have a 1/4" roughing endmill. Sticking that in the mill I was able to hog out 2mm per pass.



I was careful to leave about 0.3mm for a cleanup pass with the previous 4mm endmill, and that worked out great and fairly swift too.


Having taken the base out to clean it from all the swarf, and having to use some taller parallels in the vice I re-gripped it in the vice to mill out the little steps at each end. This meant having to use the edge-finder on the bottom edge and the left edge to re-zero the DRO's




Then it just took a moment to mill the steps.




Then I removed the base and set up my little tapping stand, put some tapping lube in each hole to be tapped, and set about tapping M2.5 taper, 2nd, and bottoming taps.




So I ended up with this




Next up will be bending up some steel for the upright which supports the crosshead guide and cylinder. Somewhere down the line I will be using my faceplate on the lathe for the 1st time ever!! I'm looking forward to that.


Thanks for watching,

Tim

[spuddevans]

I've been thinking about bending the Standard up, and came up with one thought. What if I was to mill shallow V grooves in the inside centre of where the bends should be. (shown by the red arrows in the pic below)




I figure no more than 1mm deep, max 1.5mm (the steel I have is 1/8"). This should make the bends more likely to be square and at the right place. Also because the bends are close to 90 degrees it should close up the groove mostly and then I can either fill it with JB weld or soft solder.

I figure that because I am doing a smaller scale version, but this Standard is being made out of the original thickness steel, I will have enough material to shape/file/mill/grind a better looking radius on each bend if needed. With only machining a V no more than half way through the bends shouldn't be too sharp.

What does the collective wisdom think?

I'm open for any and all suggestions. If I can get away without working with red hot steel I will, but if it needs heat to bend it so be it, I'm just concerned about getting the bends in the right positions (I don't know if I can heat it that accurately)


Tim

[dsquire]

Tim

Why not try milling the V groove in a piece of scrap and bending it. That should give you a pretty good idea of what it would look like and be easier than making the whole part then finding that it doesn't work. That's how I would go about it. 

Cheers 

Don

[spuddevans]

Why not try milling the V groove in a piece of scrap and bending it.

 

I never thought of trying it out 1st on some scrap


Thank goodness for the collective 

I will definitely try that when I'm next in the workshop.


Tim

[Stilldrillin]

Hi Tim.

It's really nice to see you're back in production mode, after all the distractions...... 

Hope your lovely workshop's working well for you.   

I'm settled in. Watching......... Good luck! 

David D

[spuddevans]

So, following some great suggestions I entered the workshop brimmed full of confidence and dug out a bit of scrap which (and this reflects just how confident I felt) was big enough to actually make the Standard.

1st up was to mark out the spacing of the bends.




I decided to 1st of all try just bending it, so I stuck it in the vice and squared it up.




And for the 1st bend I clamped a length of 10mm steel bar to it




That got it bent most of the way before I had to remove the clamp and finish it off with a lump hammer.




Then the 2nd bend followed pretty easily, this time I just used the lump hammer with a steel spacer.




And the 3rd bend also went ok




The 4th bend is where it got more difficult. I managed to bend it but got the bend about 4mm in the wrong place, thus giving me a really wonky standard. With nothing to lose I straightened the 4th bend out and tried again, this time I blasted it with the blowtorch to soften it a bit.

It worked ok, and though it looks a little beat up, I had a plan to make it look better.




I popped it upside down in the mill,




And took very shallow cuts (as it wasn't fully secured) until both legs were milled equally (the rest of the legs would get cut off)




Then I cut off the excess and then using a 8degree angled parallel I clamped it at the edge of the vice, and put a 6mm ball-end endmill in the chuck.




And made several passes until the wall was cleaned up.




I did this on the other side as well, then mounted the Standard right-way-up on some parallels and cleaned up the top surfaces.




Then on to cleaning up the inside faces. I mounted it upside-down on the same 8degree angle, but this time with a couple of scrap ali' pieces




And milled the inside faces, being careful to reduce both sides equally.




Then it was only the under-face of the top. I used a 14mm endmill to do most of it, then had to change back to the Ball-endmill as one side was not quite right.




Now all I have to do is clean up the outside round-overs, thin it down to 20mm wide, trim the ends, drill for the mounting screws, then mount it on the base, bung both on the lathe faceplate and cut out the big hole on the top.





Thanks for watching,
Tim

[spuddevans]

I got a little bit more done today. I started to trim the legs to length. To make sure I got it central I used an edge finder and touched off both angled sides of the standard to find the centre, then moved over to mill off the excess.

I then realised that because of the profiling I did with the ball-end mill, there isn't now enough room for the head of a M2.5 bolt (or dare I tempt Jo with the possibility of some studs and maybe acorn nuts)

So I chucked up a 5mm endmill (and deftly caught it) and milled a couple of recesses.




Then flipped it over and repeated




A couple more shots







I left it in the vice so that I can drill the mounting holes the next time.

Onwards and, umm, sideways

Tim

[spuddevans]

Today's update...

I started off by centre drilling for the 4 mounting holes, as you can see there wasn't much clearance!!




Then that was followed up with a 2.7mm drill.




Then I needed some M2.5 bolts. I had to cut them down to size.




Little aside...

With these small screws, I just cut them off with my electricians wire cutters. But that leaves the threads  a little mashed up



So I just chuck them in my cordless drill and introduce them to a grinding wheel while spinning at top speed




Gives me this, much better.




With 4 screws shortened, I made an assembly. (ok only 2 parts, but that still counts as an assembly doesn't it?)




The plans now call for mounting this assembly onto the faceplate on the lathe to bore out a recess and true the top up. Not having used the faceplate before I was finding it quite hard to get it centred up. So my next mistake was to give up on the faceplate and have the "Bright Idea" of using the 4jaw independent chuck instead, figuring that it is so much easier to centre.

It was much easier to centre it, but as it turned out, it is also quite easy while centring to disturb the seating of the workpiece on the jaws, thereby throwing off the alignment. I didn't notice this until later.




Anyway, I bored the hole and then faced the top




But it was only when I removed it and checked it with a couple of squares and it is off slightly.




It isn't noticeable at the moment, but I'm toying with the idea of what I should've done at the start, namely kept it on the mill and bored it and faced it there.


Thanks for watching,

Tim

[spuddevans]

Today I started where I should've started the last time, by putting my little assembly into the mill vice to true up the top surface and re-bore the hole, and I blued (blacked  ) up the top with a permanent marker.




Then I pulled out my little flycutter and lowered until I just started scraping off the marking.




And 0.2mm depth of cut later,




Then I used my edge-finder and found the dead centre of where the hole should be, and then ran boring head down a few times until I had centred the hole, maybe 0.5mm bigger than it was.




I then started thinking about how to clean up the outside bent corners of the top of the standard. I remembered I had a set of "Routing" bits that I bought for my Dremel-type tool.




They are HSS (the box says) and I have used some of them on Brass before, but never on steel. I decided to give it a go, but to go really gently and with shallow depth of cuts.

I selected the one circled in red, and stuck it in the mill. It kinda looks lost in the ER32 chuck.




And before long, well actually after quite a while, (I was only taking 0.2-0.5mm cuts) I had one side done.




The finished standard (for the moment, after seeing InkyEngines VR75 I may also do something with the sides of the standard)




Next up will be the crosshead guide.

Thanks for following,

Tim

[ieezitin]

Tim.

I really like the little profile with the router bits, i take it they were intended for wood but i have used them like you on soft stuff. 

Anthony.

[spuddevans]

i take it they were intended for wood but i have used them like you on soft stuff. 

Yes, you're right. They're not TCT but HSS, so I didn't think they would hold up cutting steel, but they did. I just took it really gentle on feeds and really light cuts. I also used some cutting fluid to help things along.

The bit seems to have held up ok, should be usable if I need to "Decorate" any other parts of this build.


Tim

[spuddevans]

So I want you to imagine that, lurking within these 2 innocent looking brass bars are both a 22mm flange and a crosshead guide. One will take more imagination as I only got making the crosshead guide today.




So I stuck the thin one in the ER32 chuck in the lathe and whittled the body down to 14mm and then marked up the shoulder for the flange.




Then turned the shoulder and drilled the centre out to 9mm




Then to make sure the drill hadn't wandered I used a boring bar to open it out to final dimension (actually I over-shot a little, was going for 10mm, ended up with 10.13mm, but I'll be making the crosshead to fit it so it doesn't matter )




Then I turned down a little shoulder on the chuck end so I would be able to see the main body length clearly.




This was because I then transferred over to the mill, and into the Spindexer for cutting out the little windows. I 1st of all zeroed the DRO's on centre and on the edge of the flange shoulder. ( 1st time using the edge-finder on such a shallow edge, 0.5mm ) You can see where the edge-finder has scraped off some of the black marker.




Then using an 8mm endmill it was simply a case of nibbling away, first one side and then the other.




Then it was back onto the lathe ( thank goodness for having a collet system that fits both machines, makes life so much easier ) where I parted off the excess stock and set about turning another shoulder, this time to fit the Standard.




I didn't measure for this, just turned a little off and kept trying the fit until it slid on easily without much play (it's going to be silver soldered so a little room for the solder to wick in is good)




Then after turning the length down a tad, and a little fettling I had this.



Tim

[vtsteam]

Looking good! I'm enjoying this very much. 

[Stilldrillin]

That's shaping up nicely Tim! 

I like how you formed the standard's corners....... 

David D

[spuddevans]

Thanks Guys 

So I got started today on the flange, chucked the bit-o-brass into the lathe and had at it




I turned it to 22mm and bored out where it sits on the crosshead guide. I then set up my little hearth to silver solder it all together.




I used Bog's trick of just cutting a ring of solder and placing it in the flux, then all you have to do is heat it.

It's been a while since I've silver soldered, and I had forgotten just how hot you have to get the parts, but I got there eventually, and once I saw the solder flow I was able to push down on the whole assembly to make sure all the parts were firmly mated before removing the heat.

Then I dumped the whole assembly into a small tupperware container that I use for pickling, filled with citric acid. And there it will stay for a few hours ( probably until tomorrow )


I then thought about the next piece to make, and decided on the cylinder.

I didn't have any brass of the right size ( some much bigger, but it seems a shame to waste so much ) so I found this old Sash weight and thought that would do.




So after waiting for the bandsaw to cut it (and feeling very grateful for having a bandsaw) I faced up one side.




Then turned over and started to face the other, when this happened.




I hit a hard spot, in fact, I hit it going one way, then sharpened the flycutter and hit it again on the way back 


So after thinking a little I remembered Rob Wilson and his carbide flycutter and then noticed that my carbide lathe tools are the same size as the flycutter HSS.

So...




That got it smoothed over. It does a really good job. I just love the silky smooth feeling of fresh flycut metal.

Then as I had a fare bit of material to remove I switched to a 3/8" roughing mill, and was quite surprised to see that my mill was able to take a full width cut 2mm deep




Then once I had it down to dimension, I moved on to the edges.




And then I ran out of time. Next up will be finishing off the other side. Then once all the sides are to dimension I can start turning it into a cylinder. Isn't it funny how often preparing and sizing the stock takes longer than then making the part.


Tim

[spuddevans]

So before I got re-started on the cylinder I dug the standard out of the citric pickle, gave it a rub over with an old rag, the joints looked ok, waddya think? I will be facing off the protruding bit at the top.




After hacking off the excess of the cylinder blank, I roughed it to size and finally finished it to size with the flycutter




Then after using the edgefinder to zero the DRO's and then spotted for the top cover




Then drilled it



Then did the same for the the lower end,




Then it was the turn of the valve porting side, spotted




Then drilled,




Before finally joining up the holes in the top and bottom ports with a 2mm endmill.




That sounds all very simple, but it took me all afternoon. I think it was because I was converting from imperial to metric while scaling down and all the while not screwing it up.

Hopefully I have succeeded.

Next will be drilling the angled holes through to each end of the cylinder from the ports. Then it will be over to the lathe to bore out the bore and turn the flange ends.


Thanks for watching.
Tim

[spuddevans]

So I started off today by drilling the exhaust hole in the side of the cylinder, it's drilled 2.5mm and will be tapped M3




Then it was time to drill the angled holes to connect the valve to each end of the cylinder. The plans call for them to be drilled at 25 degrees, and not having a tilting vice or a sine-bar setup, I used the next best thing that I did have, a set of angled parallels ( I don't know why they are called parallels as there is only one of each angle )

However the biggest angle is only 10 degrees, so here was my (not-very-pretty) solution, use 3 angled parallels stacked (10, 9 and 6 degrees) (A sine bar setup or tilting vice is definitely on the to-do list)




However crude it looks, it worked. I guess in Elmers engines there is a lot of "wiggle room" on the absolute accuracy of work.


My next great idea was to spot the face with an endmill before drilling, so as to give a level (relative to the drillbit) surface for the bit. However, because of my scaling down the dimensions, I needed to use a 1.5mm or smaller endmill. Not having a 1.5mm endmill I changed chucks and used a 1mm carbide endmill. I know that normally you shouldn't use a drill chuck to grip endmills, but my ER32 chuck wont grip a 1mm shaft.




It all ended up being irrelevent anyway as I was unable to down-feed slowly enough and the endmill just snapped off. So I then did what I should've done 1st, and used a centre drill to spot the face.




and then drilled through with a 1.3mm bit




After repeating on the other end (without the snapping of a 1mm endmill) then it was over to the lathe, and the 4jaw.

Using a wobbler-pin-thingy in the centre drilled centre hole I had drilled in the mill, I centred the bore (or where the bore should be)




I'd been waiting for this for a while and it happened today, things went a little wrong.

If you noted on the above Pic, I used some scrap ali pieces to protect the jaws from marking the cylinder, however I had not paid attention to them and I didn't realise that they were so rough and a little tapered. This had the effect of pulling the cylinder out of square with the jaws.

I didn't realise this until I had drilled the bore 10mm (eventually to be 12mm) and then faced the end off. That's what gave me the clue that something wasn't right, instead of taking 0.1-0.2mm off, I took off nearly 0.5mm.

I should have stopped before taking off so much, but my zeal ate me up.

I then realised that if I was to carry on then everything would be well off, so I took the ali shims off and reclamped without them, and re-centred the drilled bore, re-faced the end, and then set about opening up the bore with a boring bar.




I opened it up to 11.8mm and then used a reamer to bring to final size 12mm.




Hopefully the cylinder is not too short now.


At this point it was feeding time at this zoo so I finished there. Next up will be turning the flanges on both ends, then it will be back onto the mill to shape the outside of the bits between the flanges.


A little off topic, but as I was about to leave the workshop I thought I'd show a little habit I've got into in the workshop



This highly advanced, and may I say, Patent applied for, device is a hanging impliment  for my workshop overalls. After reading many horror stories about wearing jewellery  around machines I have been determined to form the habit of exchanging my wedding ring for my overalls as soon as I enter the workshop. It's now a habit, a good habit I think.

(thus endith today's lesson)


Tim

[spuddevans]

Today I started off by turning the flanges, and it was while I was turning them down to size I found that with my previous mistake with initially gripping and turning off-true has also caused the bore to be off-centre by about 0.3-0.4mm. It's not too bad but it will mean some extra work to try and cover it up as you will see later.




Then it was back onto the mill to mill the little steam/air passage from the previously drilled angle ports so that they meet up with the bore.




Then it was onto shaping the outside of the cylinder, as there was about 3mm depth to come off I used my 3/8" roughing mill to get to within 0.2mm of depth and width,




before switching to a 10mm carbide (no real reason for using carbide, it was just the only 10mm endmill I had, which saved changing the collet in the mill) to bring to final size.




Then, according to the plans (which I am trying to follow as closely as I can, but I think there would be a few things I'd do differently another time, more about that in a bit) I needed to mill 2 45degree sections before (optionally) rounding over. I have already decided not to round it over but to leave it semi-hexi so that solves that, but how was I to hold the cylinder at 45 degrees without a tilting vice or sinebar (or enough room to use many many angled parallels) ??

I had a cunning plan ("was it as cunning as a cunning fox who went to oxford university, majoring in cunning?"  "Yes Baldrick") I dug out 2 M2 grub screws and inserted them thus,




Before placing into the vice and holding firmly against the moving jaw until tightened.




This setup is not the most secure, so I took somewhat lighter cuts until I had this,




After doing the other side and then spending a few mins with some 400grit emery to clean up the "whiskers" I had this




That was the angle that makes it look better than it actually is. I said earlier that my mistake led to a slightly off-centre bore, well that meant that the previously drilled and tapped holes on the flanges were also off-centre.



and




So what to do??? They are off by about 0.3-0.5mm. I suppose I could fill with some threaded rod, solder it up and re-face and then re-drill and tap. I could live with it and try and disguise it in the cylinder end caps (I guess only the top will be readily visible)


What I should have done is not drilled or tapped any of the flange mounting holes until after the cylinder was bored out, it would be far easier to find the centre of the bore and then drill the flange mounting holes. But that's what you get for blindly following the instructions poorly.

At least I didn't drill the mounting holes on the top of the standard assembly yet, so I can use some of those M2 grub screws sharpened to a point and inserted into the cylinder to copy the off-centre mounting holes.

Whatever I do it is going to take a bit of thinking and no doubt extra work in machining to get round this.


Thanks for watching,

Tim

[spuddevans]

After a bit of thinking I came up with a plan of action.

I started by gripping the cylinder in the mill-vice, and using my edge-finder I centred and zeroed the DRO's on the exact centre of the bore. I checked 3 times to make sure I was bang on centre ("We don't work to the thousandth of an inch, we work until it's dead on!")

Then using a wiggler with a pointed end I found the centres of all the offset flange holes.




And duly noted all the DRO readings on the whiteboard for both ends of the cylinder. Then I was able to work out exactly what the offset for each end was, and my guesstimate had been right, about 0.3mm out.




Armed with this vital information I then proceeded to make the cylinder top cap.

I chucked a bit of Brass into the lathe and faced it and also took a cleaning cut off the side, only a skim as it is a 22.5mm bar and I want 22mm.




Then, throwing all caution out the window I went with my gut and transferred over to the mill to drill the offset holes. Unfortunately my gut forgot to tell me to take any pics of the drilling, but I'm sure you all can imagine what it looked like.

Then with abandon I decided to keep it in the mill reasoning that I have it centred and the DRO's zeroed on centre, so why not mill the little register that goes into the bore of the cylinder. With some thought I realised that I could use my boring bar with the tool turned the other way and the mill reversed. And you know what, it worked fine.



Perhaps a little slower than doing it on the lathe, but setting it up in the 4jaw would have cancelled any time saving.


Then it was merely a case of returning to the lathe, roughly centering it and then parting it off.




And with a couple of M2 socket cap screws (I didn't have any short enough for the 2 blind holes, but will shorten some later on) holding it to the cylinder.




Next up will be the slightly more complicated "inboard cap" with it's packing gland.


Thanks for looking,

Tim

[Stilldrillin]

I like what you did with the boring bar, Tim! 

That's thinking outside the box........ 

David D