Resurrecting a Stuart 10V

Br,

That would have been the best option but like Dr_GMJN I put the drain cocks on the side rather than at the back. I will finish the brass insert for the steam ports and the have another look at the various options you have all suggested.

Many Thanks,

Colin

[This posting has been removed]

Talking of lagging - how about trying varnished wooden strips with a couple of brass securing bands? That might look a bit different.

Although it's a No4 the wood goes well with blue Doc

I like that. Maybe a shade darker and bit of satin varnish on the wood, but yeah. I do like it.

Planning to do a wooden parquet floor for the Princess Royal base, just to add a bit more interest and to help scale it.

Same colour scheme on the engine and beds as the 10V.

[This posting has been removed]

Why not? They were made to be built. Be good to have another 10V thread.

Cut and squared a block of brass up on the Cowells mill. Then for my own sanity blued it and scribed the port locations.

Having then files the corners ensured it fitted the location in the cylinder and sat flat on the bottom.

Yesterday evening I sat and wrote down all the DRO positions and moves I needed to produce the slots. To make it simple (for me) I worked from centre lines in both X and Y axes.

Used the Cowells mill to do the slots as exhaust port was going to use a 3/32" and inlet ports a 1/16" slot mill. There is a lot more feel on the tiny machine for the little slot mills. But even with this I still snapped a 1/16" as I was half way through the last port.

Once I had finished the two inlet ports I revisited the corners of the exhaust port with the 1/16" and plunged it down to tighten up the corners.

It deliberately sits proud of the cylinder port face as I will face it off when JBWeld has gone of and then lap it.

Whilst I had the 1/16" slot mill in the chuck I centred up the slide valve and opened the recess up to its correct dimensions.

Slowly but surely.

Tomorrows task is to JBWeld it into place and look at top cover.

Colin.

Looks good to me.

I hope you've taken some "before" pictures of the engine and parts, as a comparison.

JBWelded the insert in yesterday morning. Looked at it at 8 in evening and had not gone off. Had left it compressed in the flypress in workshop. Obviously not warm enough. Found suitable machine clamp and clamped it together and left on bathroom radiator for 10 hours. That cooked it.

Into the mill and ran facemill over the top. The drilled guide holes through the brass into the casting at points coinciding with original exit of diagonal hole. Set up at 25 degrees and drilled through from end of cylinder to meet up with drilled hole. I had cleaned the echaust pprt up as much as possible before the JBWeld had gone off and ran a tap back down it. Set it up in mill and ran a long centre drill down to meet up with drilled hole.

Pretty happy with the end result. Just needs lapping.

In the end I opted to use a 3.5mm slot mill to remove the 5 tapped holes for the top cover. Before i did this I hunted high and low for some cast iron remnants to use to plug the holes. Eventually found a 20mm length left over from the spigot on the cylinder for the CHUK2 I had recently made. It was 20mm diameter and had a hole in one end. Was it going to be enough. I slit it lengthways to give me four triangular sections 20mm long. Was able to roughly centre this in the three jaw chuck and the checked whether it would stand a interrupted cut and took one piece down to 5mm dia, Happy I could do this I the set the cylinder up in the mill and because I could not trust that the holes were on an accurate PCD I set each hole up one by one with Isoma optical centre.

The swapped to 3.5mm slot drill and took first hole down to 4mm depth. At this point I finished turning the cast iron down to just over 3.5mm dia and checked fit in hole. All okay so repeated exercise for each hole in turn. End result below.

I turned my bits of cast iron down for each hole in turn. I found that the slot mill cut slightly bigger in couple of cases so took the rod to 3.55mm.

Loctited pegs in place and have left on radiator overnight.

Will clean up (and square up) top of cylinder tomorrow and if necessary make a new top cover. Might bling this up and do it in brass.

Colin

Re-finishing that cylinder will be very satisfying.

Do the lower holes in the cylinder and standard correspond in a position that makes the valve chest square to the crankshaft?

Dr_GMJN,

If you look at the photo half way down previous page you can see the holes which connect to the standard. These are out slightly but nowhere near as far as these were. I think with the top corrected this will not be anywhere as near noticeable, especially with reversing gear fitted.

Colin

I was thinking more for function than aesthetics - the centre of the valve chest boss should be over the axis of the crankshaft, otherwise the valve rod mechanism could bind. Still, you had it running, so it can’t be too far out, if at all.

Edited By Dr_GMJN on 07/02/2021 23:15:43

If the holes in he cylinder AND the standard are off by similar amounts their squareness to the port face will not matter.

Can't quite remember where, I think maybe one of Jason's engines but the wooden floor was run diagonally across the base which I thought looked really good and different to, just a thought. 

Edited By Ron Laden on 08/02/2021 07:40:04

Ah but it was parallel to the engine

Ah yes I forgot that part

Sorry, we had better get back to Colin,s engine.

Yes, but given the other alignment issues I just wondered.

Left the Loctited inserts overnight on radiator to cook and go off.

In the mill this morning to face down and square the top face to the port face. Then used Bolt Hole on DRO to position the new holes and tap them 7BA. Think they look a lot better. Manage to get the top cover to fit by opening up the clearance holes.

Lapped the port face and cylinder end faces and did a quick reassemble and test run.

A significant difference. Turned the air down to 25psi and would still run. I know this is still quite a lot but not plumbed up properly as yet just using airline nozzle, so losing a lot of air.

One thing interests me. How much of the inlet ports should be exposed when the slide valve is at the limit of its travel. If you look at the picture below I would say that around two thirds is exposed. This is the same for both extremes of slide valve travel. Would I be correct in saying all of the port should be exposed for best performance. My thoughts are that the slide valve is fractionally too long and needs a quick skim of each end.

Colin

Just check the valve is 1/2" long, it won't uncover all the port but the area exposed will be greater than the area of the drilling into the end of the cylinder so that's where the restriction is. Probably about 1/64th left uncovered.