# Stuart No. 4 build



## smfr (Feb 25, 2012)

I've started work on a set of Stuart No. 4 castings that I was lucky to pick up on eBay:





It has the crank as a casting, which I guess means that it's an older set? As far as I know, all the parts are present. I also have a casting kit for the reverse gear.


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## smfr (Feb 25, 2012)

Step 1! The boxbed:





This is just basic squaring up on the milling machine, though space on my milling table is limited so clamping gets slightly interesting:





There's a shim under the lowest corner to stop it rocking. Once the underside is done, we flip it over and mill the top side flat:





Here I have to move clamps around, because I don't have enough travel. Note the 'L' on the lowest corner (found on the surface plate with a height gauge), so I know what height to start the cutter at.

I was hoping one of the "No. 4" imprints on the castings remains on the final model, but I suspect they all get cut off.


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## smfr (Feb 25, 2012)

Next up, the soleplate. Again I had to get creative with clamping due to limited table space:





Note the stacked clamps! It's suboptimal because the whole thing could swivel around the one bolt, but the rotational forces are minimal when just trimming the bottom.

Once the bottom was flat, I flipped it over and went over the top surface, then cut the bearing slots. Here I messed up slightly: rather than center the slots on the entire casting, I started by centering them on the bearing bosses, but then found that those bosses are not centered, so I had to correct slightly. The slots are a bit oversize, but it's not an issue as I just cut the bearings to fit.





While it was clamped down, I also drilled and spotfaced the holes for the corner bolts. The plan doesn't show the spotfacing, but it's certainly required for the nuts to sit flat.

In the photo above I've completed one bottom bearing, making it a snug fit to the slot. Here's the other bearing being squared up:





I swear this gunmetal squirms under the cutter. I was pretty sure I'd cut the slots on these bearings within a thou or so, but the slot ended up about 2.5 thou too narrow. I took these to final size by filing, since I wanted them to be a snug fit to the soleplate.


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## Don1966 (Feb 25, 2012)

I have been eyeballing the Stuart engines and I will follow along on your build. Are the casting all metal on frame, flywheel and cylinder.

Regards Don


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## smfr (Feb 25, 2012)

The top bearings are a little more tricky. First I cleaned up the lower surface in the 4-jaw:





I then glued the two together, planning to turn the bosses. However, I realized that I had no true surface I could use to ensure that the join was aligned the turning axis, and in the center. So after some application of heat to undo the Superglue, I used a chuck spider in the 4-jaw to put a small flat on top of each bearing, with the bearings having the same thickness:









and then I could glue them together again:





The boss is then a simple turning job:





I also drilled a small hold down the center to I had a reference to re-center when I flipped it around. However, even with the best of plans...

At some point in the hole drilling, the Superglue gave way and the two sides separated. 

Also, look at that hole! It's all over the place, and (I think) not just after separation:





After some futzing around trying to get the halves aligned properly, I attached them together with solder this time, and was able to complete the other side, and open up the hole to 1/4":





I'm wondering how to ensure that things are lined up when I drill and ream the hole to size. My plan is something like this:

1. Sweat the two lower bearings together and drill to 1/4", so that both upper and lower bearings have 1/4" holes in roughly the right spot. Separate the halves.
2. Sweat the tops and bottoms together in pairs, aligning the holes
3. Drill to 27/64"
4. Drill and tap the soleplate for the hold-down bolts, and bolt the bearings down
5. Ream in place with a spiral 7/16" reamer

Does that sound reasonable?


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## smfr (Feb 25, 2012)

Don1966  said:
			
		

> I have been eyeballing the Stuart engines and I will follow along on your build. Are the casting all metal on frame, flywheel and cylinder.



Hi Don

Frame (boxbed, soleplate, standard), flywheel and cylinder are all cast iron castings, yes.


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## bronson (Feb 25, 2012)

I also love stuart engines and will follow with great interest. Really liked your beam engine repair thread. Great start on the number 4.

Bronson


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## rklopp (Feb 26, 2012)

This brings back memories. I built a Stuart No. 4 when I was in the 8th grade. It took a long time, as it was my first model and I had no milling machine (or milling attachment at first). I built it using a South Bend 9" Model A and a drill press. That was nearly 40 years ago. It had a forged crank. The model still lives on a shelf in my office. I look at some of the alignments and fits and cringe, but that's what experience does to you.


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## Don1966 (Feb 26, 2012)

Please get some good photo shots of how you bore the shaft bearings. I would try to line them up on the mill after bolting them to the base plate and drill and ream them through if height is not a problem. I have not done this before so I am curious. I like your lathe spider I need to make my own. Good progress so far thanks for pointing out the mistakes.

Don


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## bearcar1 (Feb 26, 2012)

Hi SM', First of all let me begin by saying I really enjoyed watching your re-work of that Stuart beam engine, that was some very good work. An I have to agree with Don about drilling/reaming that C.S. hole on the mill. If you have an angle plate, bolt the base casting, with the bearings attached to it, and proceed that way. Both holes will then be in exact alignment and at the correct center height. I'm watching with interest and look forward to your progress.

BC1
Jim


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## smfr (Mar 4, 2012)

Not too much progress over the past week. I think I've got as far as I can with the bearings until I receive the 7/16" spiral reamer I got on Ebay. Here's where I'm at:





The upper bearings were separated, then spot-faced with a 7/16" end mill and drilled. I have yet to tidy up the ends, but know that I'll use the rounding table, and pivot around the opposite bolt hole.

I still need to sweat the two lower bearings together to start the hole. Then I think I'll sweat uppers and lowers together and clean up the hole, then put them in the sole plate to see if things line up. I have a feeling that if I drill and ream them in place in the sole plate, the lower bearing is going to be oversize or misaligned. Maybe I'll do a dry-run or two at a smaller diameter to see how things work out.


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## steamer (Mar 4, 2012)

".....Maybe I'll do a dry-run or two at a smaller diameter to see how things work out..."


A very wise course of action.  :bow:

Dave


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## smfr (Mar 6, 2012)

I thought I'd take a break from the bearings, and made some progress on the standard over the weekend. After some cleanup with a file, I wrung it onto lap that I had lying around:





which allowed me to do some initial cleanup on the feet. This setup isn't rigid enough to do a good job, but I just wanted to get the feed good enough for the next step. I'll finish them off later.

I made a couple of feet clamps:





and used them to attach the standard to a faceplate. Now I used the same lap to get it mostly centered:





I could then take a facing cut across the top. However, when trying to take the top diameter down to size, I was getting a lot of chatter, because things weren't rigid enough, so some support with a live center in the tailstock was used which helped a lot.





Now came the part that I was a bit nervous about: boring. I pretty soon found out that chatter was a serious issue here too, but worse because the boring bar has some flex also. I bolted some 1-2-3 blocks to the faceplate, and to each other with some Al bar spacers. This worked pretty well, once I'd adjusted things to avoid pulling the standard out of alignment.





I also tried to reduce resonance in the boring bar by wrapping it in electrical tape, but that didn't seem to do much. (I suspect that chatter often results not simply from lack of rigidity, but also from the part and tools resonating or "ringing".)

The new setup worked pretty well, though the interrupted cut in the middle of the standard taught me that not all carbide inserts are created equal ;D (Yeah, I know, I should't be using carbide for an interrupted cut, but I have no HSS boring tools or inserts.)

After boring to a few thou undersize, I made an Al lap:





My poorly conceived plan was to screw a pipe tap into the lap to expand it, but that didn't really work very well. Luckily the lap was tight enough at the start to still be useful.

I applied the lap with a couple of grades of diamond paste:





which resulted in an acceptable bore.





This bore is spot on 1 1/8", but I would have liked to be able to take perhaps another thou off by lapping to improve the finish. Maybe I'll figure out a way to make the lap work better and apply it again.

Next is to flip the standard around on the faceplate and finish off the feet to take it to final height. I'm noodling over the best way to hold the thing to keep those feet nice and rigid.

I'm also not sure if I should clean up the windows in the bore with a mill, or just leave them as-is.

Simon


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## steamer (Mar 6, 2012)

Those feet pose a problem with a interupted cut.

I would suggest a HSS tool with some top rake and a keen edge to cut that.
Carbide doesn't like interupted cuts and you won't get the finish you want either

Keep the tool narrow and with a very small radius to prevent chipping. 

Alternatively, you could use a similar set up that your used with the faceplate and 123 blocks, but on the mill and mill the feet.  I personally would do it in the lathe ....with light cuts and patience.

Dave


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## zeeprogrammer (Mar 6, 2012)

Stuart models was a big reason I got interested in this hobby.
I've never made one but always wanted to.

Watching with great interest.
Great job!


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## steamer (Mar 6, 2012)

If I were to do it in the lathe, I would make a sacraficial faceplate and clamp the cylinder flange to it.  More rigid and less likely to damage.


Dave


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## rhankey (Mar 6, 2012)

Nice to see you are working on another Stuart. This one looks like a nice old casting kit from back when the casting quality was much higher nd they still included cast or forged cranks. I would imagne this one will be quite a joy to machine and build, and even more so when you aren't rebuilding someone else's mistakes. I recently got myself a very old Stuart twin launch csating kit to dig into after I've completed the Stuart triple that I'm about 60% through building. The quality of the early 1960's castings in the twin launch are amazing.

It is interesting seeing yet another perspective on how to make parts. I'm discovering that 10 different people making the same part will have at least 11 different ways to get the job done. Once the part is made, you'd never know they were each made with such different methods.

Happy building.

Robin


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## Don1966 (Mar 6, 2012)

I am so glad to have join this forum. As robin has point out everyone has his own way of doing this and it just amazes me how the human mind can come up with so many unique ways. Looking good Simon I would like to build one some day,so I will be staying the coarse.

Regards Don


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## smfr (Mar 8, 2012)

I decided to clean up the feet bottom on the mill. A bolt down through the bore was a convenient way to hold it down, and I used a heavy angle plate and some clamps just to add a bit of mass at the feet to avoid vibration:





I did quite a bit of checking with the indicator to make sure that everything was straight, since my milling table has 50 years of wear on it 

I took off 18thou with a sharp 1/2" end mill, and the final height is pretty close.

The flange around the feet also needs some cleanup, which I'll just do with a file, and I'm using this setup to make sure that the ends of the feet are roughly equidistant from the center line. The arbor I used to lap the bore makes a convenient holder, in a V-block. I held it down by hand while scribing the top foot, then swiveled it 180° and scribed again.





That's the standard almost done, other than drilling some holes and cleanup with files.


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## lazylathe (Mar 8, 2012)

Looks like another great start on another great model! ;D

Love all the pictures of set ups used, they will come in handy one of these days!

What kind of mill do you have?
The table looks very nice!

Andrew


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## steamer (Mar 8, 2012)

Whatever gets it done is the right way!  Well done! :bow:


Nice setup.

Dave


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## smfr (Mar 8, 2012)

Andrew: the lathe/mill is an Emco Maximat "Standard" (1961/62):





It's actually a mix of two machines (I swapped in the less worn bed).

It's great for a combo machine (all I have room for), but it's a real pain that the table is so narrow. It makes setups really tricky sometimes, and I can't even fit a decent vise on the table (like a D30).

Simon


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## lazylathe (Mar 8, 2012)

Thank Simon!
Looks like a great combo machine.
And it looks to be in near perfect condition too!!

You do great work on those machines!
Keep it coming!

Andrew


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## steamer (Mar 9, 2012)

Hey Simon!

I'd like to second Andrew's comments.  You have come a long way for a "new guy".  You prep and execute like a pro.

Well done!

Dave


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## smfr (Mar 12, 2012)

Did some work on the cylinder today, and in the process, discovered an error in my machining of the standard 

When I bought this casting set, it came with a photocopy of the original plans (dated 8-12-53). Since parts of those were dark and hard to read, I bought a new set of plans from Stuart Models, which, of course, go with the more modern castings. Well, it turns out that some parts have changed!

The 1953 cylinder is 2" long, whereas the modern one is 2 1/8" long. The 1953 cylinder flanges have a 2 3/8" diameter, and the modern one is 2 9/32", etc.

What this means is that my cylinder is too long, and the top flange on the standard is a bit small. Nothing I can't make up for, but annoying nonetheless :-\

Anyway, on with the build. I'll work from the old plans from now on!

The cylinder was chucked up in the 4-draw, and the non-critical top surface faced off. Then I flipped it around, taking care to seat it so that the ends would be parallel, and faced the bottom end, taking it close to what I thought was the correct length  [Not enough care taken, apparently; the ends aren't parallel, but the bottom end is perpendicular with the bore, which is what matters.]

Without removing it from the chuck, I then did the bore with a boring bar with carbide insert. I was trying to hit about 1.498", but I think I ended up with the tool just rubbing when I was trying to take the final few cuts. Still being undersize, I went to remove another thou, and the tool then started taking off material again, resulting in a bigger cut than I wanted. It ended up around 1.499" before lapping:





Not a great finish or diameter, but not too bad.

I'd earlier splashed out on an expending brass lap for this build, so then spent some time lapping the cylinder with 3 grades of diamond paste:





The cylinder is held by hand and gentled moved to and fro, so the lap extends about half way out on each side, trying to avoid making a bell-mouthed bore. After perhaps 45 minutes of lapping, and 3 grades of paste, the result is reasonable:





and measures about 1.502".

I think to get a really smooth finish I'd have to go to about 1.505", and it would take forever with a lap. Maybe a cylinder hone would be better for this? I would also worry when going much larger about whether the piston rings will still fit OK. I think I'll leave it as-is for now.

So, because of my plan mix-up, I need to take 1/16" off each end of the cylinder. I'm going to have to be really careful to keep the bottom face perpendicular to the bore, so I'm thinking of making an arbor, and using that to trim the ends. Hey, at least that lets me correct the non-parallel ends


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## smfr (Mar 12, 2012)

I also cleaned up the port face today. First I set up the cylinder on a nice angle plate that I got recently, with the base of the cylinder against the plate, so that the face is parallel with the bore:





Not ideal workholding with with just one bolt, but it worked fine. I'm using the square to set the rotation correctly.

I also left a bit of cylinder bore peeking out so that I can pass a small bar though that and through a hole in the plate, which lets me pick up the top of the bore with a height gauge. I can then use that to scribe a line so I know how much to take off the face.

Over on the mill, I used a older end mill to get through the crust, then a sharper one to take it down to final level:





That was it for today.

Now the plans call for the cylinder flange diameter to be reduced to 2 3/8", and they should flow nicely in to the inlet and exhaust port faces. I guess I'll trim up the flanges using a rounding table, but blending with the faces is going to be tricky! Also, the ports in the casting are already a bit oversize, so I'm not sure how to account for that in cutting the exhaust port.

It's too bad that the top of the standard is 3/32" undersize because of my earlier boo-boo with the plans, but I don't think I want to reduce the cylinder and cylinder cover diameters to match. Or do i?


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## steamer (Mar 12, 2012)

smfr,

If you need to take the cylinder flange down and you want to maintain squareness to the bore, make up an expanding mandrel or a tapered mandrel and pass it through the bore and set up between centers.

Then you can face both sides if you like.

Nice looking bore from here! :bow:

Dave


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## chuck foster (Mar 12, 2012)

hi simon 

as others have said "looking good" 8)

one word about the lapping, it was explained to me that one should not use diamond paste as diamonds are for ever.
meaning that the diamond grit can and will get embedded into the cylinder wall and can cut into the piston/rings as the piston travels back and forth.i would guess that very good cleaning of the bore would prevent this from happening. :shrug:
i am not an expert by any means but that is what i was told and i am sure some one on here will know for sure.

keep up the good work and i look forward to the next progress report.

chuck


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## steamer (Mar 12, 2012)

As long as the lap is softer than the item to be lapped, the diamond will bed into the softer lap and not the cylinder. I think with a brass lap and a cast iron cylinder your fine smfr.


Having said that, make sure you clean the bore well when your done!

Dave


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## Don1966 (Mar 12, 2012)

Looking good Simon, keep the input coming. I like it when you point out the mistakes its more learning on my part. I have just purchase the same lap you were using, are they any good? I have not used mind yet but a I was planning on using them on a bronze cylinder, but reading what Dave said I don't think it is a good idea now.
Have not seen any photos on the boring of the pillar block bearings,have you done them yet?


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## steamer (Mar 12, 2012)

Don,

You could try a soft aluminum lap and some silicon carbide lapping paste.  Like Clover.


Dave


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## Don1966 (Mar 12, 2012)

Thanks Dave that is what I had intended to do after what you had posted. That is what I used on my last engine. I learned something here that I never realized thanks to you. I have only built three steam engine the one in my profile was my second.

Don


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## smfr (Mar 12, 2012)

Hi Don

I haven't done the bearings yet. Rather than bore, I was planning to drill and ream them, although that requires that I make the crankshaft spot-on ;D

I'm waiting for the reamer to arrive, so I haven't tackled that yet.

Simon


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## vcutajar (Mar 14, 2012)

Simon

Thanks for your well explained build log. I assume you bought the brass lap from the UK. Could you tell me from where please?

Vince


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## smfr (Mar 14, 2012)

I'm in the US, and the brass lap came from Travers:
http://travers.com/skulist.asp?r=s&n=||UserSearch1%3Dbrass+lap&q=block+id+112470+and+class+level3+id+29980


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## vcutajar (Mar 14, 2012)

Simon

Thanks all the same. For some reason I assumed you were in the UK. I can't seem to manage to find something like that in the UK.

Vince


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## Ramon (Mar 14, 2012)

It's looking very good Simon. 

I'd like to concur with Chuck re the diamond paste and lapping. I've done quite abit of lapping using normal abrasive - silicon carbide etc and have various grades of diamond too. The information I have always been guided by using diamond is that diamond paste will bed into 'soft - ie unhardened metal - and conventional cleaning - ie solvents - can leave traces which will wear a piston/ring if fitted. If it is used then using an ultra sonic cleaner is the recognised way of ensuring all traces of diamond are removed.

Re your comment on honing - unless you have access to a honing machine honing using the sprung loaded two or the three stone brake cylinder hones will certainly improve the finish but will take a long time to remove even a couple of thou with the attendant possibilty of bell mouthing the bore. 
Personally if the finish is acceptably smooth I would make the piston to fit the bore - about 2 thou down on diameter - and if the engine is not to be worked hard on steam just use square section PTFE packing as a ring. Unlike an O ring this will create it's own seal with fairly open tolerance. I have had very good results using this method, superb piston seal and compression with minimal friction and great longevity but whilst I have run them on semi dry steam mainly they have only run on air 

Hope that's of help - Ramon


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## Jeff L (Mar 14, 2012)

Simon ,so far your works looks nice as always. 
 For Lapping I have used a product called Timesaver Lapping Compound according to the label it's "guaranteed not to imbed in metals" , and "guaranteed not to continue to cut" . I bought the yellow label stuff and it states "for soft metals only". Jeff


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## Don1966 (Mar 15, 2012)

Jeff I got mind from http://www.penntoolco.com/catalog/products/products.cfm?categoryID=5641 you can buy them seperate or as a set. I bought the set.

Don


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## smfr (Mar 18, 2012)

Today I made an expanding arbor to use for trimming the cylinder casting down (I made it too long after reading the modern plans, which are different from the older ones).

This was my plan for the arbor:





There's a tapered section of the bore, to take a tapered plug that would push out the sides. The drawing doesn't show it, but I had an M8 bolt going down the middle, which I could clamp down.

Luckily I had a bit of 1.5" Al stock lying around, but I only had to skim it before the cylinder slipped on. I wish I'd had a bit more to remove:





Once the outside diameter was close, I started on the bore. Time to get out the big drills 





After drilling to 7/8", I used a boring bar to do the rest of the bore, leaving material for the taper. It was a pain to get behind that shoulder, and a lot messier inside than in the diagram. Oh well, no-one will see it :

Lastly I set my compound to about 7°, and did the tapered section. I then removed the chuck, with the workpiece still in place:





Then I put in the 3-jaw and do the plug. Here I'm cutting the tapered plug to the same taper as the arbor:





The plug was a bit of scrap that was already tapped 3/8", which was fortuitous; I drilled it out to 17/64" for clearance for an M8 bolt, but that left enough of the 3/8" thread that I could screw in a 3/8" bolt to pull the plug out of the arbor. Here are the final bits:





I was expecting to have to cut slits, but actually it expanded just enough to hold the cylinder without them. So, finally, I could slip on the cylinder, tighten it up, and work on the cylinder. I checked the previously "good" end to see how far out it was, and saw less than half a thou wobble on the end.





I don't think it was that good after I'd done one end and flipped the cylinder around; I suspect that not being able to skim more off the arbor allowed the cylinder to sit slightly askew. I'll be careful to find the "best" end, and make that the one that attaches to the standard, since being perpendicular to the bore is what matters.


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## steamer (Jun 12, 2012)

My condolences smfr.  It happens....


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## gbritnell (Jun 12, 2012)

We've all been there! Take heart and start over.
gbritnell


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## vcutajar (Jun 12, 2012)

Hi Simon

Glad you are back. There is always one part in any project which I always have to redo. I have already done the shaft of the cam twice in the Kiwi and I have a suspicion that I have to redo it a third time. Only consolation is that the more you redo the same part, the quicker its finished.

Vince


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## rhitee93 (Jun 12, 2012)

It's good to see you at it again. That is an interesting way to build up the split bearing. I never would have thought of it that way.

Is there enough clearance in the engine design to run it with a con-rod that has a reverse taper? I think I'd use it as it is as long as there is room to clear the small end. It is a great looking part, and if it functions to boot, then there is nothing to worry about


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## smfr (Jun 12, 2012)

rhitee93  said:
			
		

> It's good to see you at it again. That is an interesting way to build up the split bearing. I never would have thought of it that way.



Yeah, I wondered whether it was a sensible way. It's very wasteful of material, but it does ensure that it's easy to drill the holes aligned. I'm sure I could have got away with two rectangular hunks of bronze. If I had steel bar of the right size, I would have used that too.



			
				rhitee93  said:
			
		

> Is there enough clearance in the engine design to run it with a con-rod that has a reverse taper? I think I'd use it as it is as long as there is room to clear the small end. It is a great looking part, and if it functions to boot, then there is nothing to worry about


I'm sure there's room in the engine, but it would bug me every time I look at it!


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## Don1966 (Jun 12, 2012)

Hi Simon glad to see you back and mishaps do happen just regroup and pull yourself up and hit it again. If you look under my post you will see my saying " how many times I did that!"
The engine I am working on now has plenty of redo's and broken taps. It all comes with learning. Sometimes I will ask why me? But I find myself starting to think things through a lot more now because of the mishaps. The learning process is starting to kick in and hopefully less redo's.

Don


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## bearcar1 (Jun 12, 2012)

I don't suppose putting the piece back between centers and making it into a fish-bellied rod would make you feel any better? ??? ;D

BC1
Jim


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## smfr (Jun 13, 2012)

I wasn't looking forward to hogging another hunk of steel, so I picked up what was left of the gunmetal casting, and decided to make a franken-rod of the old and new parts! I'd use the gunmetal casting, but re-use the split bronze bearing from previous mistake.

One of the tricky things with castings is that they don't have any flat surfaces, so setting up a datum, especially on something this shape, is a PITA. I had previously marked some centers on the ends. Does anyone have a good tip for picking up a punch mark on the side of something? I feel like some combination of bench centers and a dividing head would be good for marking out rough parts with rotational symmetry.

Anyway, I managed to square up the little end of the casting as best I could, as well as sawing down the remains of the big end, then set up in the vise:





I trimmed down the big end with an end mill, then laid out the little end hole accurately from that, taking the thickness of the split bearing into account, and drilled and reamed for the crosshead pin.

This makes it clearer which parts I'm reusing:





The end cap needs milling down, which was a bit tricky since there's so little to grab onto. Paper shims in the vise helped to avoid slipping, and it was OK. Since there's a bit of play in the bolt holes, I use some drill rod bits to align the two holes before tightening up the bolts:





Here I'm checking that the punch holes on the two ends are reasonably aligned by shimming up one end with shims that correspond to the difference in radius of the two rods:





And here we are, reading for some turning (again!)





First I turned the shaft down to a constant thickness. Just as before, the bolts get in the way of finishing the top surface of the big end:





but I can unbolt it, and that cylindrical shaft allows me to mark out a center point on the upper portion of the casting:





which is lightly center-drilled. This will be hidden by the bearings after assembly.





Now this part of the casting can go onto the lathe for turing between centers. Here I'm setting the angle of the top slide; I have an indicator clamped onto the top slide, I zero it at one end, then crank away with the little handle ;D, looking at the delta between the two ends. When this is roughly equivalent to the difference in radius between the two ends of the taper (1/64" in this case), I know that the angle is close.





Of course, before cutting I double-check that the taper is going the right way 

Success!





I left a little shoulder on the right-hand side for decoration (though I wish I'd considered the final thickness of the part, since I ended off skimming parts off this).

More to come...


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## smfr (Jun 13, 2012)

Now to clean up the big end with the split bearing. This is where it starts looking more like a connecting rod.

First I made an expanding arbor; chucked up some 1/2" cold-rolled rod, and turned down 1/2" at the end to 7/16", which is the bore diameter of the bearing. Then I drilled and tapped for M6, and countersunk. I'm going to use a countersunk screw to make it expand. I sawed cuts at 90° to allow for expansion (another successful slitting saw operation!).





Now the conrod is attached to the arbor and can be turned. Here I've started to clean up one side.





It's so satisfying seeing the casting and the split bearing merge into one as they get turned down together!

I have to be careful to take the right amount of each side; here again I wish I had some better setup for measuring.

After turning both sides, here's where I'm at:





Sadly I can't test the fit on the crankshaft yet, because the crankshaft journal has a pretty significant radius that I need to replicate on this bearing. I need to think about whether to grind a tool to cut the radius, or do it some other way.


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## vcutajar (Jun 13, 2012)

Nicely done Simon. Recycle and reuse.

Vince


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## Blogwitch (Jun 13, 2012)

Very nice rescue Simon, you've done a great job on it.

You will find that you will always have problems marking out castings, purely because they are all sorts of shapes and angles. 
Having investment castings (lost wax process) helps a lot, and on those, because of the way they are made, they don't need release angles etc, so come out almost perfect size and shape, but they are usually very expensive.

I get around the marking out problem by machining a datum to work from, then at the very end, rough up the machined area to make it look like it was original.

But of course, everyone has their own way of doing things.

Nice one :bow:


John


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## rhitee93 (Jun 13, 2012)

Nice save! It is actually better than the original design


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## bearcar1 (Jun 13, 2012)

Well done!

BC1
Jim


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## Don1966 (Jun 13, 2012)

Nicely done Simon, I knew you could do it. 

Don


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## smfr (Jun 18, 2012)

This is almost where I left off last time:





but I've done some hand filing on the end cap, and drilled and reamed what will become the bottom of the yoke. I regret not leaving a bit more material at the small end of the taper, but I think it will be OK. I decided to form the bottom of the yoke because I wanted to shape the shoulders, and to know what the profile will end up like.

I broke out the ball-turner to form the shoulders, turning between centers of course:





It's always a bit of a puzzler to work out the combination of placement and rotation with this thing, and I usually end up doing it by eye.

Next up was cut out the center of the yoke. For most of the material removal, I had the part clamped in a screwless vise. However, as soon as I broke through the bottom, the part loosened and moved slightly; not a big deal but stupid here then decided to just tighten the vise, which squished the Y, pushing the sides of of alignment ;D. Some judicious hand-bending with some 1/4" drill rod through the crosshead pin holes got it back into shape!

So to finish off the Y, I clamped it down securely:





Then it was onto the rounding table to finish off the radius on the end:





The top arm is flapping in the breeze a bit with this setup, and had enough flex that I think it was getting pulled up by the end mill, resulting in a non-square profile. I was able to flip the part over and tidy that up, however.

A bit of draw filing, and the part is almost done:





What remains is still to put a radius on the journal bore to fit the crankshaft.


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## gbritnell (Jun 18, 2012)

Very nice save Simon. There should be no problems with the journal strength with the extra material below and above. 
gbritnell


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## smfr (Jul 2, 2012)

It's been a few weeks since I've managed to get time in the shop (garage!), but I got a few things done today.

Here's my setup for the crosshead milling:





I have the crosshead on the piston rod in a V-block, because I want the milled parts to be parallel with the piston rod. The angle plate etc. is just there to line things up. I clamped my screwless vise on its side around the crosshead for milling, which made things a little cramped:





After doing one side, I had to tear down the setup, turn the part around (making sure that the side to be cut is parallel with the part I just milled out, using the height gauge). Had I been thinking more clearly, I would have had the V-block on its side for the first part, then I could have just flipped it over.

Once both sides were milled, the crosshead pin hole was drilled and reamed in the same setup:





Here's the result, with its companion connecting rod:





Before milling, the crosshead was a nice sliding fit in the standard, but the milling pushed those skinny flaps out (this being bronze), and tightened everything up. A bit of fussing around was required to get it sliding in the standard again.

After that I drilled and tapped the boxbed for the studs that hold down the soleplate. The alignment of the soleplate on the boxbed was mostly by eye/feel. I transferred the holes by positioning the two parts under the mill, with the clearance drill bit just dropping into the existing hole in the soleplate. I then switched to the smaller tapping drill size, and drilled down into the boxbed. The 4 holes were then tapped 2BA.

One annoyance here is that the stud holes in the soleplate go down the inside corners of the casting, which ends up pushing the drill out of line, and causing the studs to catch. To fix that I milled out some room on each corner, centered on the holes:





I'm close to being able to have this thing crank the crosshead up and down! I spent some time fitting the split bearing on the connecting rod to the crankshaft journal, but it still needs some wearing in.





I just need to drill and tap the studs for the standard, and make the crosshead pin, and then I can have it turn over.


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## vcutajar (Jul 2, 2012)

Way to go, Simon. Still here folowing your progress.

Vince


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## steamer (Jul 2, 2012)

Nicely done Simon!

Nice trick on the back column squaring device!

Dave


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## ShedBoy (Jul 2, 2012)

Looking real good Simon 
Brock


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## Don1966 (Jul 2, 2012)

Nicely done Simon and glad to see you back at it. It looks like it is starting to take shape now. I will be here till it is complete.

Don


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## NickG (Jul 3, 2012)

Nice work on the castings Simon, just finding a few more projects to watch and haven't seen a Stuart No. 4 done before, keep up the good work.


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## smfr (Jul 5, 2012)

Got some shop time in today, since it's a holiday!

First up, I marked out and drilled the bolt holes in the standard:





and drilled and tapped the soleplate for these bolts. I had left this until now because I was worried about getting the alignment right, and wanted to be able to assemble the crosshead and conrod with the crankshaft to make sure everything lined up. Luckily things fitted just fine.

Next up was the crosshead bolt (which I called a pin earlier, but the plans refer to it as a bolt). This started as a bit of stainless from the scrap bin; the first part is a simple turning job, taking care to get a nice 1/4" fit to the conrod and crosshead:





Checking the fit on the conrod:





It's important here that the nut will bear down on the shoulder of the bolt, rather than the conrod arm, otherwise the nut may loosen when the engine runs. I have a bit to take off the yoke of the conrod by filing, but it's close.

Then it's threaded 2BA, with an undercut at the end of the thread so that the nut seats nicely:





I flipped it around, held it in a 1/4" collet, and carefully parted off the excess:





then turned the head. Almost done:





I'm using temporary fasteners for everything so far, hence the ugly nut. Oddly, the fastener set that came with these castings has been blackened. I'm not sure if Stuart shipped them that way for a while, or whether the previous owner did it. Or maybe it's just from storage?

There's one more bit on this bolt/conrod to do, and that's a 1/16" pin that prevents the bolt from rotating. This sits right on the edge of bolt's shaft. Here I've drilled the corresponding hole in the conrod:





I took care with the setup, using an edge finder on some 1/4" rod situated in the hole, then offsetting to find the center of this pin. I was worried about the teeny drill wandering into the main hole, but it was OK.

Without changing the setup, I then dropped the crosshead bolt in, tightened the nut on the other end, and clamped it down to prevent it spinning. Then I could drill a matching 1/16" hole for the pin, and guarantee alignment:





Final crosshead/conrod/bolt parts:





I need to find a 1/16" pin somewhere. Any ideas?

After some more fiddling to fit the conrod bearing to the crankshaft journal, I was able to put everything together and give it a spin on the lathe. It's all pretty tight, so needs a good bit of running in:

[ame]http://www.youtube.com/watch?v=5z6fSfN6XRc[/ame]

(Sorry about the crappy vertical video.)


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## tomfilery (Jul 5, 2012)

Simon,

Nice work - as usual!

For your 1/16" pin, I'd use a piece of blunt 1/16" drill shank (I tend to keep them in the scrap box, rather than throwing them out for just this type of situation) - you might need to anneal it to allow you to cut/ file it.

Regards Tom


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## mzetati (Jul 5, 2012)

If You want to keep it hardened, You can cut it with a disk and eventually taper/dome/finish the ends with a dremel wheel, while spinning the pin into the lathe.
For soft pins, I've used nails.

Marcello


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## Don1966 (Jul 6, 2012)

Hi Simon glad to see you making more progress. It is starting to really take shape now that you have overcome your obstacles, things should get a little smoother with completion near. Great work as always.

Don


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## steamer (Jul 6, 2012)

Looks good Simon.....keep her well lubed!

Dave


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## steamer (Jul 7, 2012)

You could always turn up a pin for the rod..... ;D

Dave


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## Florian (Jul 7, 2012)

steamer  said:
			
		

> You could always turn up a pin for the rod..... ;



That was just my thought 5 minutes ago, and now i see someone just had exactly the same idea... 8)

Cheers Florian


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## steamer (Jul 7, 2012)

It was the sites new mind reading function! *beer* ;D

Dave


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## smfr (Jul 9, 2012)

Guess what I found in the old fixings jar? Not one, but two 1/16" pins  The newer fixings set that I got recently from Stuart for this engine didn't have any, so I'm glad these castings came with their own fixings set.

Made some good progress today. I'd been putting off milling the exhaust steam passage, but did so uneventfully, after carefully marking out the exhaust slot, and the exhaust hole on the side (with the same center height, of course). The two inlet holes were pretty wonky in the casting, and one is a bit wider than the other, so I tried to center the exhaust as best I could between them. Milling was starting with a 3/16" end mill, and finishing off with a 1/8", then the corners were filed square.





I probably should have drilled the 1/4" exhaust hole first so I could just mill down until I hit it, but did it the other way around, and it worked out OK.

Given that the steam ports aren't quite equally spaced, I wonder how smoothly the engine will reverse once complete. One possible solution would be to make a plate with accurate ports, mill a recess in the casting and silver solder it in, but I'm not keen on doing that unless I absolutely have to.

While I had the cylinder set up, I also drilled and tapped the holes for the exhaust manifold thing, and the lagging screws. Interestingly, the older models used a 5BA lagging screw (left side below), and the newer ones a 7BA (right side; the screws are in the exhaust manifold holes; I'm just trying to compare them visually here); I chose 7BA for now.





Now to drill for the drain cocks: spot-face, center drill, drill through and tap 3/16" 40TPI:





and the cylinder done except for the stud holes on each end:





So, lots of stud holes to drill and tap: 6 on one end, and 4 on the other. I broke out my recently purchased 4" Phase II rotary table, centered the table under mill (via an MT2 arbor in the center hole), then centered the cylinder casting on the table. Boy, clamping things on this teeny table is tricky!





Once everything was aligned I cranked the carriage along by half the bolt hole diameter, and I'm ready to go!

I drilled the top cover and the tapping holes at the same time (the cover was clamped for drilling), turning in 60° increments, then enlarged the holes in the cover to clearance size. Then I went back around the holes for tapping; I found that the rotary table was precise enough that I could accurately return to a hole position, which is nice. I started the taps in a chuck in the mill (turning by hand) to keep things straight.

6 holes tapped, and the moment of truth: does the cover fit?





(Spot the odd stud out!) Yay! In fact it fits in any orientation, so I guess I counted the rotations right 

After that I did the 4 stud holes on the base on the cylinder. 4 holes this time, so line things up, rotate 45°, drill, crank 90°, drill, crank 90°etc. I jotted down the angles, and used those to double-check my handle-turning count. 

Drilling the standard really pushed the limits both of clearance on my mill, and clamping on the rotab. I could just get the drill into the chuck, and don't look too closely at my clamping job here 





I was relieved when all the drilling and tapping was complete without any broken-through holes and broken taps. Now for the fun part, assembly:





Wow, this thing is beginning to look like an engine 8)

Next up will be the piston rod gland. I'm a bit concerned about alignment there, having read another recent thread here about that. I have the right taps and dies (1/2" 26 TPI), but I wonder if single-point threading would be something to consider, having never done it before?

Thanks for following along,
Simon


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## swilliams (Jul 9, 2012)

Looking good Simon. I'm enjoying following your build. Your Emco seems to be a great option for someone with limited space

Cheers
Steve


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## steamer (Jul 9, 2012)

Definitely looking the part Simon!  I wouldn't get too wound up about packing glands. If you did the piston and rod square and true, the packing shouldn't be a problem.  Does this engine have a screwed in packing, or bolted in packing?

Dave


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## gbritnell (Jul 9, 2012)

Very nice work Simon.
It's been many years since I last built a Stuart but they sure are nice looking engines.
gbritnell


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## kvom (Jul 9, 2012)

The port spacing shouldn't be an issue; just make sure that the valve travel is centered on them and not on the exhaust.


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## Don1966 (Jul 9, 2012)

Very nice job indeed Simon, it is starting to look like an engine. Like Kvom said you should have no trouble with the port spacing. 

Don


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## smfr (Jul 9, 2012)

Dave, the packing gland is screwed in (with a hard-to-find 1/2" 26TPI BSB thread!). I actually made a quick tail post die holder for the die, and cut the thread already:





but I did that after reaming for the piston rod, and I'm wondering if it would have been better to tap the bottom cylinder cover, screw it down onto something to simulate packing, and then ream it in place. The risk is that it then only lines up at that particular orientation. I think it's OK for it to be a little oversize though.

Steve, I'm pretty happy with the Emco. The main limitation for milling is the tiny table (about 5" by 9", and deep rather than wide). Not even enough room for a decent 4" vice! I wish I'd kept the spare carriage that I had, so I could have ganged the two carriages together somehow.

Simon


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## Florian (Jul 9, 2012)

Hey Simon

Well, if you want do get it absolutely true, you would have to first ream the bore; then use a turning mandrel to put the part on and then turn the threads between centres. 

Else, it works quite good if you make a cone to the beginning so the die starts taking cuts with slow increasing depth.. 
(puh.. that was difficult to explain, didn't know how to describe that with the cone but I hope its clear what I mean...)


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## smfr (Jul 9, 2012)

I understand what you mean by the "cone" on the end; take a small cut at an angle on the end (which means making the part over-sized to begin with, perhaps), matching that angle to the "starter" angle on the die. That assumes that the die is accurately ground, of course!

I guess I can use a similar trick to get the tap accurately centered in the cylinder cover casting (which the gland screws into).


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## Florian (Jul 9, 2012)

Well, that with the cone itself would have been easy - what I wanted to say is that the cone angle should be very small, something like 10°. 
And I don't know how you call that kind of cone - guess its not "small cone" 

Cheers


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## smfr (Jul 10, 2012)

I plucked up the courage to thread the bottom cylinder cover for the piston rod gland today this evening. To hold the cover, I put the soft jaws onto the 3-jaw chuck, clamped the jaws down onto a bit of stuck, and cut a lip to fit the cylinder cover, then removed the stock and clamped down on the part. Here I'm checking with the dial indicator; runout was about a thou, which seemed reasonable.





Then I put a small bevel on the bore so that the tap would start concentrically:





I was concerned about tap alignment, so fiddled around for a bit with shims under the leading edge of tailstock, and the drill in the chuck that I'd use to drill the part earlier, and got the drill sliding nicely into the hole. Then it was replaced with the tap, and tapping started under hand power, with the taper tap:





With this size tap it wasn't long before the tap was starting to rotate in the chuck (despite backing out the tap often to clean the chips), so more desperate measures were called for! The steady rest made a handy way to keep the tap straight so I could apply more force with the tap wrench:





I switched to the bottoming tap, then back to the taper tap, then back to the bottoming tap, and by the end was using two wrenches to turn the thing (but carefully!), and finally was done.

Hey, I can make it finger-tight, and the piston rod still slides through 





The threads in the cast iron look terrible, but I'm not sure how much of that is my fault. These are HSS taps from Tracy Tools in Devon, UK, but they don't seem to cut as nicely as the HQS taps I have from Tap & Die.

Simon


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## steamer (Jul 10, 2012)

Hey Simon,

A Karma from me for creative use of a steady rest! ;D

Looks like you got it beat!  The gland bore doesn't need to be dead tight, a couple of thou clearance won't hurt it and the packing will take it up....but it seems you don't need to worry about that.

Nice Job!

 :bow:

Dave


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## NickG (Jul 10, 2012)

Yeah nice work with the steady, I sometimes support it with a tailstock centre and let the tap wrench come up against the cross slide but depends on whether the tap has a centre.

Soft Jaws has definitely got to be the best way for cylinder covers and the like, I've never had any but they look worth their weight in gold for such applications.

Top job :bow:

Nick


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## ShedBoy (Jul 10, 2012)

Nice job Simon.
Are they roller bearings in the steady rest?

Brock


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## rhitee93 (Jul 10, 2012)

It's looking good Simon. I'm excited to see this one run


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## idahoan (Jul 10, 2012)

Simon

I have been enjoying your build; the work on the cylinder is great.
I have given you a Karma point for the use of soft jaws.

Dave


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## Don1966 (Jul 10, 2012)

Great job Simon, l like your soft jaws that is next on my list of acquisitions. Looking forward to seeing it complete. Keep up the good work. 

Don


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## smfr (Jul 11, 2012)

ShedBoy  said:
			
		

> Are they roller bearings in the steady rest?



Hi Brock

Yes, a previous owner did a hatchet job on the bronze fingers and fitted bearings; one of them isn't even square :-\ They leave marks on even steel parts, so I don't really like them. It would be easy to make new fingers; they are just a push fit.

Thanks for the comments all! Work is easing off a bit, so I have some more evening time to work on the engine now.

Simon


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## smfr (Jul 11, 2012)

I left the piston rod gland set up in the rotary table last night, so couldn't resist drilling the 7 holes (capstan holes?) tonight.

I put an MT2 collet in the center hole of the rotary table, holding a spare piston rod (1/4"), so could use that to center the bottom cylinder cover with piston rod gland on the table, and allowed me to clamp the cylinder cover:





I did have to move the clamps around for the different holes though. I did 7 holes, 51° 26" apart, counting turns on the rotary table handle (hmm, could I have used the dividing plate? Not sure if it does 7's), with a 1/16" drill.

All done, lightly countersunk the holes by hand:





I did a quick assembly of the engine with the piston, and even without the piston rings, or any bolts holding stuff together, was getting some reasonable compression in the cylinder. This is quite exciting! Of course it probably means that the cast iron piston is a tad oversized; I think I want about 0.002" of clearance for a cast iron piston in a cast iron cylinder, with cast iron rings?

I think I'll work on the valve chest and value parts next. The eccentric strap is probably the most tricky part left; I'm going to make the simple value fittings first as practice, get it all working, and then do the reversing parts later.


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## vcutajar (Jul 11, 2012)

Simon

Still following your progress and enjoying your setup photos and explanations. Keep it up.

Vince


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## Runner (Jul 11, 2012)

Simon,

I note that you've been focused on building the engine and not sidetracked by the running-in issue that you raised. Add my applause also for the use of a steady rest when tapping the gland boss. It is a trick that I shall use in future. It demonstates a methodical approach to the task. Your engine will be a fine example when finished. Good luck with drilling the steam passages (or did I miss that?).

Brian


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## steamer (Jul 11, 2012)

".......I did have to move the clamps around for the different holes though. I did 7 holes, 51° 26" apart, counting turns on the rotary table handle (hmm, could I have used the dividing plate? Not sure if it does 7's), with a 1/16" drill......"


YUP you could use an index plate....if you have them for that table...
Do you know what the ratio is of the table and what hole counts you have with the plates?

Dave


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## Ned Ludd (Jul 11, 2012)

Hi Simon,
When you have difficulties tapping, provided your tap isn't as blunt as a boxing glove, try opening the hole slightly. It will reduce the %engagement slightly but you will be surprized what you can get away with. You don't have to follow slavishly the books on tapping sizes.
Ned


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## smfr (Jul 11, 2012)

Runner  said:
			
		

> I note that you've been focused on building the engine and not sidetracked by the running-in issue that you raised.



Thanks Brian! I'm pretty sure all the tightness is in the connecting rod on the journal, and there because of the radius on the journal ends interfering with the sides of the split bearing. I just need to work on that some more.



			
				Runner  said:
			
		

> Your engine will be a fine example when finished. Good luck with drilling the steam passages (or did I miss that?).



The steam passages were cast as part of the cylinder casting, so the exhaust slot was the only one that needed drilling out. I can blow through the steam passages, so I assume they don't need clearing out.



			
				steamer  said:
			
		

> YUP you could use an index plate....if you have them for that table...
> Do you know what the ratio is of the table and what hole counts you have with the plates?



I just looked it up, and I could have used the dividing plate; the one for this little 4" table is somewhat limited, but does 7s (it has a 28-hole circle). Darn, missed a chance to use a tool for the first time!

Thanks for the continued interest,
Simon


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## steamer (Jul 11, 2012)

".....I just looked it up, and I could have used the dividing plate; the one for this little 4" table is somewhat limited, but does 7s (it has a 28-hole circle). Darn, missed a chance to use a tool for the first time!..."


Yea.....but you won't next time... ;D

Keep at it man your doin fine!

Dave


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## Runner (Jul 11, 2012)

Simon,

revisiting your picture using the steady rest I note that you use a nut and bolt to stop the gland from turning in the soft jaws. Little things like that are indicative of your planning skill. Think twice do once!

Brian.


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## RCGUY (Jul 11, 2012)

Simon,

I have a rotary table like yours and was considering some MT2 collet's for it. Where did you get your collet's, are they short and have a draw bar?

Ed


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## smfr (Jul 11, 2012)

RCGUY  said:
			
		

> Simon,
> 
> I have a rotary table like yours and was considering some MT2 collet's for it. Where did you get your collet's, are they short and have a draw bar?



Hi Ed

The collets came with my lathe; the previous owner had assembled a set, and a couple of them are shorter (which is very annoying, forcing you to swap draw bars!). I see MT2 collets on eBay, which are probably equivalent quality to what I have. The longer ones are a bit too long for this rotary table; I think they stick out of the back slightly.

Brian: I added that nut and bolt after the part started to rotate 

Simon


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## steamer (Jul 12, 2012)

The things we make teach us a lot don't they!
 :big:

 :bow:
Dave


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## smfr (Jul 15, 2012)

I worked on the valve chest today, which seemed to be a bit slow going.

First step after marking up: square up the inside a bit. No critical dimensions here, just need room for the valve to move.





This kit is old enough that the valve guide is cast into the valve chest; the newer models have a brass fitting that you machine separately, then screw in. I suppose that avoids having to drill deep through the valve chest and adds some brass bling, but I think I prefer the old way.

Anyhoo, the valve chest was chucked up in the 4-jaw with some backing, and a wiggler and indicator used to center on the punch mark at the end of the valve guide:





I started with an HSS ground tool bit because of the interrupted cut, and to take the crust off the casting. Towards the end I switched to a carbide insert tool, which does risk getting chipped because of the interrupted cut, but actually performed fine. After a bit of turning we're close. Both radii were done "freehand" and cleaned up with files. Here I'm using a radius gauge to check the shaping on the end:





and in this photo the neck radius still needs some cleanup. With a bit more work it's almost done:





but I still need to get rid of some tool marks around the base.

Now it's time to drill and ream for the valve rod. The angle plate on its side serves as a useful way to hold the casting square (the sides have already been machined), and we locate on the punch mark:





The top end is drilled then reamed 3/16", and the bottom end has a 1/8" hole reamed into the valve guide. Luckily, for the lower hole, I had an extra long drill that I'd picked up at a yard sale or flea market a while back, but of course it wandered all over the place when trying to enter the bottom of the casting.

My solution was to clamp a block of Al inside the valve check, switch back to the stubby drill then drill through that to form a guide for the longer drill.





This worked nicely; with the block still clamped, it acted as a guide for the longer drill which no longer wandered, and I was able to complete the lower hole, then ream 1/8".

The upper hole was also opened up to 3/8" using a small boring tool; the valve rod gland fits into this.

I now pondered long and hard about how to do the profiling on the lower side of the valve chest. I guesstimated from the plans that the curves have a radius of 1", then blend into a radius around the bolt holes. To machine the curves, my options were the rotary table (setup too hard on my tiny table), the faceplate (easier setup, but hard to control the radius from the center), and the 4-jaw. After hatching a cunning plan to get the right offsets, the 4-jaw won.

I used a scrap block of Al as a simple fixture, and computed and marked out two punch marks:





When the fixture is located in the 4-jaw with the appropriate punch mark centered, I know that if the valve chest is clamped against the fixture the right way around, I'll hit that 1" radius for that side of the valve chest.

Here's the 4-jaw setup, with the fixture clamped in the middle, and the casting held by just one jaw.





Not an ideal way to hold something in the 4-jaw, but the setup was pretty rigid so I wasn't too worried. I've already centered the fixture on punch mark no. 1, then I had to fiddle around a bit to get the casting lined up (using a square to align the chuck, and a height gauge locating on a drill bit which was a tight fit into the reamed hole). I've mostly finished one side in this photo.

After doing both sides it looks like an eye 





I didn't quite get things lined up, so there's a bit of a step where the machining of the two sides comes together; I'll have to clean that up by filing later.

Back onto the mill, using the angle plate setup again, to locate, drill and tap the holes for the gland screws:





Now another crazy setup ;D I wanted to round off the corners of the "eye" shape on the rotary table. The only way I could figure out how to hold it was on the angle plate:





There's a little rotary table under there somewhere! Usual rotab drill: locate the rotary table under the mill and clamp it down. Set up the part on the table, also centered (I used a drill bit dropping into one of those tapped holes for location). Now use the carriage to adjust the radius being cut.

I don't have any ball-end mills of the right radius, so I milled a few steps, then cleaned up with a file. Here we are, one side done:





This part is on the underside of the valve chest, so I don't have to get too crazy with finishing, and it might even be painted. I can never decide whether to paint valve chests!

Tomorrow I hope to finish the profiling here, mill the chest down to thickness, do the valve chest cover, and drill and tap for the studs that hold the valve chest to the cylinder.


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## steamer (Jul 15, 2012)

Hey Simon!

Well Done!  I like your thinking and approach! and wonderful photo's!

 :bow: :bow:

Dave


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## rhitee93 (Jul 15, 2012)

Bravo! Great thinking applied to a piece of detail that many would have just ignored. Nicely done


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## Don1966 (Jul 15, 2012)

Well done Simon, isn't great when we think things though. Neat setup.

Don


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## zeeprogrammer (Jul 15, 2012)

I haven't been on the forum much lately...

But tonight right away I ran into this thread (again) and read through it.

Excellent stuff. Great pictures too.

I really appreciate the detail and approaches taken. Gives a newbie a feeling of optimism.

Most of us know the extra work it takes just to take pictures and record one's progress. Very much appreciated.

As I'd said in a (much) earlier post...Stuart models was one of the first things that got me interested in this hobby as a kid. Your work is quality.


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## rklopp (Jul 16, 2012)

Simon
Good move on the drill guide inside the steam chest. When I built mine, I was naive and did not think to use a guide. The drill walked. I ended up making the end of the valve rod eccentric, which makes for interesting times putting the engine together. If I'd only known then what I know now, 40 years hence. 
Best,
RKlopp


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## smfr (Jul 16, 2012)

Another Sunday, another day in the shop 

I got the other side of the valve chest gland profile rounded off, but here's what happens when you go a bit too far on the rounding table:





I should be able to take it out by filing.

I milled the valve chest down to about the right thickness; the outer side is non-critical, and I left is slightly thick because otherwise I start running into the radii for the valve guide and the gland thingy.

Now the valve cover gets a cleanup, first with an old end mill of unknown sharpness, to get through the crust, and then with a nice sharp one on a finish pass:





Then I did something that I might regret, which is to clean up the center indentation. Not having any ball-end mills, I used a little carbide burr that came with the Dremel:





It did the job OK, but I'll have to file away some of the machining marks. I'll need some riffler files to get into the concavity. I say I might regret it because it might make the cover look too too machined, and not like a casting. I guess it depends on how I paint it.

While marking out the valve cover for final size, I also marked out the stud holes:





It's another crazy setup!  I wanted to drill the cover, valve chest and piston all at the same time to ensure that all the stud holes lined up. So I came up with a setup, using the angle plate as a backing, a 1-2-3 block on each side between which the parts could be clamped, and some spacers at the back to align the top edges of the parts:





Some cardboard takes up the slight differences in thickness between the parts. I set this up so that, if need be, I could repeatably remove and replace the valve chest and cover to drill the piston itself. It turns out I didn't need to do that. One problem with this setup was that the holes are pretty deep, so the drill chuck could hit the 1-2-3 blocks. I had to use a full length drill bit (slightly undersize for the tapping size) to go all the way down into the piston. This worked fine, but I did manage to drill through into the exhaust hole. :-\ Oh well, that's not under pressure so it shouldn't be a problem.

The holes in the chest and cover were then opened up to clearance size (#27) with the part held in a screwless vise, held by hand. Then the holes in the piston were drilled to tapping size (#33), the 4BA taper tap started in the mill by hand, then tapping completed using a tap wrench.





Always a bit nerve-wracking on a part into which many hours have gone, but it went fine.

Now for a test fit:





All the studs look straight, which is a good sign. And the valve chest and cover fit nicely over the studs, so my drilling in-place seems to have paid off.

To end the day, some mock assembly pictures to see how everything fits together:



 



I have yet to drill the steam hole in the valve chest. I see some engines with steam and exhaust on one side (keep all the pipes together?), and some with steam in one side, exhaust the other. I'm not sure which I want yet.

Simon


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## Blogwitch (Jul 16, 2012)

I'm not criticising your work Simon, far from it, just bringing up a failure point of most Stuart engine designs.

The left hand picture above shows what I mean perfectly. The flywheel hanging in mid air.

That will ensure the all crank related bearings will get unnecessary wear on them. From the very front one (nearest the flywheel) to the back one AND the big end in between.

Just as a suggestion, I would machine up a small support, so that the weight of the flywheel is taken to task with a bearing either side of it.

Lovely work BTW.


John


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## mzetati (Jul 16, 2012)

John,

that same problem I will have the day I will bring the Bernay(s) to completion. Not yet decided whether I should fit a supplementar bearing to the wood base or make a metal plate to put both the engine and bearing on.
If I took the additional trouble of making a split bearing, eventual adjustments would be easier.

Marcello


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## gbritnell (Jul 16, 2012)

Excellent work Simon. Your documentation is first rate.
gbritnell


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## Troutsqueezer (Jul 16, 2012)

gbritnell  said:
			
		

> Excellent work Simon. Your documentation is first rate.
> gbritnell



Ditto.


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## smfr (Jul 18, 2012)

I'm going to continue documentation of this build at madmodder: http://madmodder.net/index.php?topic=7362.0


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## NickG (Jul 18, 2012)

What's happened here? Loads of posts missing etc?


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## smfr (Jul 19, 2012)

NickG said:


> What's happened here? Loads of posts missing etc?



NickG: see the "HMEM sold" thread, and other threads. Content posted here is now automatically copyrighted by Group Builder, not by the poster.

Simon


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