Stuart 10V Build Log - Complete Beginner...

Thanks Jason, I wasn't aware of the different reamer types, so I just checked and mine is in fact a machine reamer. I had a look on the Dormer website, and no lead-in taper is shown for it, so there was probably no issue. I will use the reamer and estimate the depth I need to go - the fork centre isn't machined out yet. When I machine the pin, I can make it a fairly tight fit, which should also give me the opportunity to ream the slider and work the pin with some Autosol and oil (or whatever) until it's a perfect fit.

Connecting rod next. I believe it used to be supplied as a stamping, but now it’s a rough-machined item:



For some reason, it’s got a spigot on the back. I used it to locate in the mill collet, and then lowered into the vice in preparation for drilling the bolt holes. I clocked it up beforehand to check it was straight; it wasn’t bad, a few thou runout:



And again in the vice to check all the accessible surfaces were square:



I then used the edge finder to centre the spindle:





Then co-ordinate drilled the holes. I used a smaller drill than specified in order to get a tighter fit:



Then removed from the vice, marked out the split line, and the-fitted in the vice to check its level:



Then used the thin slitting saw to cut the lower block:







Then cleaned up the mating faces with an end mill:



And removed the spigot from the lower block and milled to the correct depth:



Bolted together and Loctited, the sides were milled to the right thickness to fit between the crank webs:





And the small end faces. A bit of vibration here, but I couldn’t think how else to hold it to drill bothe ends in the same setup:



Then double checked the main faces for flatness in two planes:



Then got the centre point for the crank pin hole bang on the cut line:



Drilled and reamed:



Then on to the small end. Through drilled and tapping to 5BA:



And in the same setup, drilled and reamed half way to pin size (removing the upper threads in the process):





Next job was to measure and open out the forked end by milling:





Final job was to machine the cheek bosses. I made a simple fixture out of aluminium (thanks for the idea Jason). The end boss is a clamp and a diameter reference:











So after a quick polish, that’s another bit done:







On assembly, there was a slight resistance to turning in a couple of spots, but working with a drop of light oil soon had it working smoothly with no side play at all:





The sides of the bearing block are very close to the sole plate, but are in fact under-sized to the drawing. The slider stamping the the forked end located around is also undersized slightly as supplied. Bit of a shame Because I could have narrowed the fork. It’s only a slight bit of play though, and I may well need it once assembled...

Looking good, The CNC machined part is a lot easier to work with than the old soft gun metal casting that was supplied which most people tended to bend while trying to mill out the fork. The spigot was to hold it by while taper turning the shaft.

Thanks. I did wonder about tapering the shaft, but the Stuart book I have on building the 10v doesn’t mention it, and the images appear to show it parallel.

I guess it would look better tapered. I’m in two minds about it - I don’t really want to mess about with the tailstock of my lathe at this point. Not sure if there’s an easy(er) method? Obviously it would have been simpler with the spigot, but the sides of the main bearing block appear to be machined circular anyway, so I could easily mount it in a split bush in the chuck.

I wonder if I could turn a taper like that just by adjusting the compound slide? Might try it after getting a bit further with the piston and slider.

It's a compound slide job, would have been easier if done before milling out the fork as you can use tailstock support

Yes, I was thinking to size a block of aluminium to fit in the fork, nip it together with a 5BA bolt and centre drill it.

I think a few home made machine jacks would be of use to you. Nothing fancy, just a cylinder of some suitable material tapped through and a bolt with a smoothed off head. It will allow a far more substantial support and can be used with some top clamping to do jobs like the one where the work piece is supported by a small drill.

Martin C

Yes, I was thinking that, I suppose I should make one for drilling the eccentric arm.
In fact there are quite a few things I need to do or make that would make life easier:

DROs for the lathe, or at least some settable dials.

Thrust bearings on the lathe slide handles (not sure how to machine the holders with them removed though).

Jacks.

A spindle handle for threading in the lathe.

A DTI holder to fit the lathe tool holder.

I should have sorted these out before starting on the engine I suppose, but after fettling the milling machine it felt like enough was enough - I bought it to make the 10V, not to modify it and make tools.

I’ll get around to doing it all before I start the next steam engine kit - hopefully next year if the Doncaster show is on (unlikely it seems).

Another couple of questions about the eccentric strap:

Does the large hole need reaming, or can I somehow set it on a faceplate and use a boring bar to get a fit on the eccentric?

Also, the diagram shows a bolt with lock nuts through clearance holes through the split side of the strap. The two lock nuts look a bit clumsy. Is another option to clearance drill only the upper side of the split, thread the lower part of the split, and use only one nut to lock?

Thanks.

Bit out of sequence, but made a base today out of some spare Oak and a spot of Briwax. I used one of the slot drills that I can't seem to use effectively on metal, and a woodworking router bit for the chamfers:

I heard wood dust doesn’t do machine tools any good - something to do with silica or something in the wood. Anyway it won't be a regular thing, so I guess it's OK.

Yes the strap can be bored on the lathe or if you have a boring head it could be done on the mill. Easier to sneak up on the size when using the lathe but easier to hold on the mill.

Yes tapping and a single lock nut will also work.

Just make sure you get rid of all Oak shavings from all tools.

Thanks guys.

Any tips for holding/centering the strap in the lathe for boring, and drilling the oil hole adjacent to the arm? I guess there is a danger of distorting the hole if I clamp it incorrectly.

I'm thinking of:

1) Milling the main faces and small end boss faces to the right thickness first.

2) Then mill the sides (next to the large hole).

3) Then drill the clamp & centering bolt holes and the oil hole - not sure how to do this, because the oil hole is right next to the arm.

4) Then bore the main hole - this is where I'm not sure how to hold it.

5) Then drill the small hole on the mill.

Thanks.

It's true some woods are abrasive, but the main problem is water. The spongy bits go deep into a machine tool's delicate places where they stick, soak up lubricating oil, and cause rust. They pick up metal swarf to form a sort of grinding paste.

Compared with metal, wood is unfriendly. It's the accurately machined surfaces and lead-screws on metal-working lathes that suffer, especially the areas that are hard to clean - what's under those gibs? Woodworking machines don't have to hold high-levels of accuracy, and they lack most of the features that make mills and metalworking lathes vulnerable.

Machining wood causes trouble over time, so doing it occasionally isn't a problem provided it's immediately given a good clean. The risk is almost eliminated when the machine's sensitive parts are protected by paper sheet. I take pretty much the same precautions cutting cast-iron, which also gets into important little places and starts grinding.

Even with separate and appropriate tools, I've found cutting wood and metal in a shared workshop is best avoided. Sawdust alone is OK, as is swarf alone. It's mixing them together that causes most trouble! Nowadays I cut wood outside rather than mess with dust-sheets etc.  What do others do?

Dave

Edited By SillyOldDuffer on 21/09/2020 09:26:34

Thanks Dave.

I think the issue is that I (and probably many other people) can't justify a woodworking lathe or router (in terms of space, cost and how often it would get used), and any woodwork other than rough sawing has to be done in my garage. This weekend I was working with MDF to build a telescope mount. Much of it was done in the garage, and I vacuumed up afterwards. The lathe and mill are covered with plastic covers when not being used.

I'm no good at cutting/planing wood accurately, and I wanted a neat looking base of the engine. I've got the Mill, so I used it, even though I know it's not ideal. If I use it for woodwork again I'll perhaps use more covers.

The point about cast iron dust is a good one. I've generated loads of it during the engine build, but what do you do?

Personally I'd go for taking reasonable precautions, but use the tools to get things done, rather than just look at them and let them deteriorate through lack of use! It's a fine line between deciding to occasionally use existing equipment for something it not ideally suited for, or not doing it at all.

Cheers!

I just looked at the Harold Hall website again.

I think I'll start by mounting the stamping in a 4-jaw chuck using a spigot in the tailstock chuck to align it.

Then bore the hole and face one side in one setup.

Then transfer to the mill and do the rest of the thinning, facing amd drilling there.

Any other suggestions appreciated.

Thanks.

I take the view that tools wear out, best do something interesting with them before they do. In fact, I hope I wear my lathe out, it'll show I got my moneys worth and I can then justify buying a better one

I bought the lathe to do work. I bought a bigger lathe to make work easier. I use it for all sorts of things; last job was to scrape 16valves clean as it's quicker and easier to use the lathe than any other method I've tried. I wiped the ways before I started, and covered them with brown paper to make cleaning up easier.

Like the above poster, if the lathe wears out slightly quicker than if I babied it, it really doesn't matter. I bought it new six years ago, and use it when necessary. I doubt I'll wear it out in the next 25(ish) years.

Didn’t do much on the engine yesterday, but made a small machine jack (as per Martin's suggestion) to support the rather flexible eccentric strap end:





I might make another, just in case I ever need two, and perhaps a couple of stepped, threaded studs so I can screw secure it into a T-slot if required.