An unfinished Stuart 10h Mk I

[Sanjay F]

This is the Mark I version of the Stuart 10h. It does not have a tubular trunk guide, but has a single-sided cross head. Not sure when it changed to the tubular version?

There are several odd things about it:

- The crosshead guides are missing but have clearly never been there as there are no holes.
- The cylinder does not mate correctly with the soleplate
- Someone has got a bit trigger happy when drilling the holes in the cylinder
- There's a huge blob of solder holding the exhaust in place
- The entire engine has never had a primer or paint on it
- The piston rod end has been beaten over to try and keep it fixed to the piston (it didn't work!) - see video
- The valve chest cover has never been machined to size and it never had the 'S' on it, so must be a later addition

In my humble opinion this engine was never a runner, although I did try pumping some air through it 

I think I'll start with trying to get the cylinder sorted before moving onto the crosshead guides, new piston and rod. I cleaned up the soleplate and it looks like a brand new casting, I even had to file away some flashing; I may actually paint this one given the fact it was never finished......

I have a couple of questions.

1. Has anyone got the drawings for a Stuart 10h Mark I?
2. How do I sort the messy solder out; is it soft solder and will just melt away nicely......?

https://youtube.com/shorts/rbw4oq6WAsg?feature=share

[internal_fire]

- The crosshead guides are missing but have clearly never been there as there are no holes.

The important part of the crosshead function works as long as the rotation is clockwise, as viewed in the first photo. In either movement of the piston the force is downward onto the "crosshead" platform. Lateral restraint is not very important.

Gene

[Sanjay F]

That's great, thanks Gene, I never knew that 

[Jasonb]

Looks like soft solder so it can be melted out. A damp cotton (not manmade) cloth will allow you to wipe the liquid solder off the surface which will leave very little and that can be removed with Emery.

No Drawings but looks like the bars just had a single fixing at each end. 1/8" x 1/4" would probably do depending on how thick the lip on teh bottom of the crosshead is. Mill a rebate into the bottom corners to retain the crosshead.

[Sanjay F]

Excellent thank you, I'm hoping there's nothing nasty under the solder! You're right about the way the guides are fixed, I found the picture below of a complete engine

[Sanjay F]

Started on the cross head guides and discovered a surprise under the solder which was anticipated. The hole for the exhaust was too near the port face and was filled in with solder; I’ll think I’ll make a custom fitting and use a bit of good old JB Weld

[Sanjay F]

Managed to get a 2BA tap down the the hole and then made a little exhaust fitting; hopefully it looks better than a bent old bit of copper pipe with a blob of solder holding it in place. A little bit 'o' JB on the port face and the jobs a good'un! 

[Grateful Ted]

i’m enjoying your little ‘refurb’.
Cheers, GT

[PaulR]

Much tidier 

[Sanjay F]

Thanks Ted, Paul

It's usually this initial bit which turns up the issues and I enjoy figuring out what to do without making things worse (it doesn't always work out) 

- Cylinder has now been cleaned inside and out
- Cylinder and soleplate are now best mates after an hour with a round needle file opening up the holes on the soleplate
- The really rusty bits are having an overnight bath in rust remover

[Sanjay F]

The rust came off and after a bit of emery, the parts look better, but at the same time it has highlighted the imperfections; still its an old engine. The JB weld worked ok on the port face

[samc88]

I think I have some 10H drawings somewhere if you want them I will unearth them. Nice progress so far

[Sanjay F]

Hi Sam

Thanks for the offer, I have 10h drawings for the current model engine with the tubular trunk guide as I restored one quite recently. Its this early version with the single sided cross head which I was looking for.

[samc88]

Its the modern version I have unfortunately (not sure why as I have never had a 10H)

[Sanjay F]

Made some progress today:

- New piston & rod machined to fit cylinder - now not a rattling about
- Guide rails drilled and fitted
- Oil way drilled into crosshead
- Cylinder mounted with gaskets fitted front & back

It's all looking a bit rough it terms of looks, but that can be sorted out once the 'little beastie', as my Scottish neighbour would say, is up 'n' running ........fingers crossed!