Slapper

[PaulR]

Time to start building the engine outlined in this thread https://www.modelenginemaker.com/index.php/topic,12666.0.html even though the plan is only about half done and more than a bit vague in places 

I'm calling it 'Slapper' as the valve rod tappets get a slap from the crosshead extension on each stroke, not for any other reason although it should be easy to make and will probably be a bit rough  (maybe a UK specific joke?).

Anyway, I braved the brass monkeys to turn the cylinder and valve cylinder down to size, make a small centre hole on each then set up the first part in the slide for milling the first of two flats. That will have to wait until tomorrow as every piece of metal was so cold I could barely feel my fingers by this stage.

[PaulR]

Got the two surfaces milled for the valve cylinder and the main cylinder support. The first one went fine but the gremlins sabotaged the cross slide twice while doing the second one. I obviously hadn't got the part mounted centrally enough and wound the cross slide a tiny bit too far so had to disassemble the handle/dial/spring to turn the shaft manually with some pliers to get it back on the thread. Apart from wasting time, thankfully it didn't have any effect on the outcome.

Photo shows milling second flat while gripping on first.

[PaulR]

Taking the advice of forum experts I decided to screw the two parts together to eliminate any movement during soldering. Slight issue, I didn't have any small brass screws or a die for anything less than 3mm so I made some grossly-oversized-for-the-job screws which will be chopped off and made to disappear later. There will also be plugged holes just to the outside of them where the ports will be drilled at each end of the cylinder. Second photo shows where the cylinder support will go. If I've done it right, the complete circle of the cylinder covers will just miss the valve bore.

[PaulR]

Got those securing screws cut to length then silver soldered the parts together - still needs some excess solder removing and a bit more pickle. Next I made the two bores which seem to have come out nicely parallel although the valve bore feels a tiny bit looser than it should when a piece of 6mm silver steel is inserted. That might be a result of having to stop and reposition the tailstock due to the length of the cylinder. Not ideal but I've tried pushing the tailstock bodily along in the past with less than satisfactory results. It doesn't matter anyway as I'll be turning the valve down from 1/4" mild steel so can make it to fit.

Next, drill then plug the passages and fit an inlet tube.

[vtsteam]

 

[PaulR]

After making parts for two different designs of cylinder support and changing my mind I settled on this one which, it turns out, is probably just as bad if not worse The steel parts were screwed then soft soldered together and the whole thing soft soldered to the bottom of the cylinder. Getting it all lined up for soldering (and not having room for screws into the cylinder) was a royal pain in the a**e. Of the dubious designs I've come up with over the last year this set of parts is undoubtedly the worst. Anyway, it's done now and should be ok as longs as it holds together!

[Sanjay F]

It looks good from this side of the screen   

[vtsteam]

Looks good to me, too, Paul. You can also wire parts together for soldering by twisting the wire. A friend of mine is a whitesmith who makes incredibly wrought and hand worked locks. He does a lot of nearly invisible brazing by heating the wired pieces together in the forge, then applying the braze.

[PaulR]

In another short session in the cold workshop I made the simple outboard end cover for the cylinder. Turned the spigot and used the home made detent to mark off the holes. Switched to the drill to make the holes then back in the lathe to part off. I'd previously slimmed down the parting blade and didn't realise until I was nearing the end that the original fatter part would need to enter the cut    No biggie, I just sawed off the pip and filed/sanded it away.

[AVTUR]

Paul

During this weather how long are you spending in the your workshop and what is its temperature?

AVTUR

[PaulR]

During this weather how long are you spending in the your workshop and what is its temperature?

I was in there for about 1.5 hours this morning and it got up to a max temp of 11C. Probably down to the 5-8C range by now (it's currently 2C outside). I don't feel cold myself (thick fleece jacket, strip of thick carpet over concrete floor and a 2KW fan heater), it's just that everything is so cold to the touch that the hands get too cold in the end. Hope to get back in there a little later to start the other cover.

[AVTUR]

Paul

Thanks. Perhaps I should wrap up warm and do some workshop. At present it is 3C in there and with my heating, an oil filled radiator, it will not reach 10C until Monday when it is said to get a bit warmer.

Enough said.

AVTUR

[PaulR]

Thanks. Perhaps I should wrap up warm and do some workshop. At present it is 3C in there and with my heating, an oil filled radiator, it will not reach 10C until Monday when it is said to get a bit warmer.

Yep, I have a little oil-filled rad as well but it's pathetic and as you say takes ages to heat up. I've bought a £10 fan last week, use that to get the temp up then switch to the rad. Managed to get it up to almost 13 degrees this afternoon - luxury! 

Made the cover with the guide and the gland nut but need to undercut the thread on the latter a little more and maybe shorten it a fraction. Slightly blurry photo attached. Next up, the 2.5mm threaded holes in the cylinder for the securing screws. apart from the piston, I've pretty much caught up with my plan now so I better get stuck in and draw up some more parts!

[Michael S.]

Hi Paul,

the cylinder with the control valve looks great! The mounting brackets on the cylinder are also well done.

Michael

[Sanjay F]

During this weather how long are you spending in the your workshop and what is its temperature?

I was in there for about 1.5 hours this morning and it got up to a max temp of 11C. Probably down to the 5-8C range by now (it's currently 2C outside). I don't feel cold myself (thick fleece jacket, strip of thick carpet over concrete floor and a 2KW fan heater), it's just that everything is so cold to the touch that the hands get too cold in the end. Hope to get back in there a little later to start the other cover.

You guys have my sympathy, my old workshop was sub-zero and had rising damp in the walls, flooded everytime there was huge rainfall. I wore several layers of clothes and looked like the Michelin man in order to do anything.

I made a pact with the devil (the other half) and when we renovated the house the boiler and heating system got moved into the new workshop and that along with an small oil filled radiator gives me according to this old Bakelite thermometer what you can see in the photo!

Boy am I paying for it .....for many years!