William build

Hi

I started on Martin Evans William in February, as I am very much a beginner this seemed a sensible first locomotive. I have the book which is very helpful but doesn't answer all of the many questions that will arise!

The chassis is coming along well and I have made the water pump. My question is this. The inlet and outlet (on pump) are threaded 3/8 ins. and 5/32 pipe is shown on the backhead. All of the suppliers I can find do union nuts that are for 1/4 pipe for 3/8 thread and 5/32 thread for 1/4 ins pipe

Not sure how to get round this, I certainly don't want to start making my own union nuts! or I will never get this project finished.

Any advise much appreciated.

Richard

Hello,

In the absence of the correct union-nut/tube-size combination you can use 1/4" pipe. If this is too intrusive on the backhead or similar visible locations then you could make yourself a small reducer that can be hidden somewhere discrete to reduce 1/4" diam. tube-work to 5/32" for the visible pipework.

The reducer is simply a short piece (say 1/2" long), of non-ferrous material drilled halfway thorough 1/4" and the other half 5/32". Make sure that there is clearance between your pipes and the holes in the reducer for the silver solder to fill, clean, flux, and silver-solder.

Regards,

Phil

Thanks Phil, got it.

But is this normal to have to do this on a Martin Evans design? Seems a bit odd to me

Richard

I know that you say that you don't want to make union nuts but seriously they do only take a few minutes each to make. I have had similar issues with pipe and union sizes in the past and my standard default is to make my own, that way I get exactly what I want without trawling through supplier's lists.

Phil

Richard - I've reviewed a lot of Martin Evans' designs and they are full of easy to draw but hard to make stuff. His trademark is impossibly small screws and springs and fasteners engaged with one or two threads. I get the impression that standardizing on a few sizes of fittings was not on the agenda.

On another forum there was a guy recently writing in with problems with M.Evans' Conway design. He was making the regulator housing and trying to drill two small holes about 2" deep. Mr Evans had designed these holes with only .008" of metal between them. The guy on the forum didn't know to drill one and fit a close fitting steel pin in it, then drill the other. He drilled one, then while drilling the other, the drill broke through to the other hole. He did manage to repair it, but this is something that could easily have easily been avoided by either designing the thing with one larger hole or by designing it to be made it as a soldered assembly of two blocks and two pipes.

Martin Evans also took serious liberties with scale and proportion in some of his designs. Example - His Canadian prototype switch engine Caribou's boiler profile and proportion are completely wrong when compared to the real engines - they aren't even similar. Other people have commented that his valve gear designs leave something to be desired on some engines, and should be validated before building with software like Don Ashton's or the old Charlie Dockstader programs.

Back when he was doing build series in Model Engineer magazine, people would write in with errors they had found in his drawings. It was very rare that he would respond at all. I don't ever remember him writing "sorry, my mistake" or the like. Pretty haughty if you ask me, we all make mistakes. Better to own up and get on with it. One of the things I really liked about the late Mr Neville Evans, designer of Fair Rosamund, Penrhos Grange, etc was that when he occasionally made a design or drawing error he would add a short bit to the end of the next article called "Cockup Corner" and publish his error and the fix. He was a class act.

If I were setting out to build any Martin Evans design I would give serious thought to modeling it all in CAD first and getting rid of some of the foibles mentioned above.

Jeff

Thanks for the advise, I just hope I don't hit too many problems! William is after all meant to be a beginners engine.

Regards

Richard

Not too many serious errors on Williiam ( I made one) but there is a clash of moving parts around where the

reach rod connects to the lifting arms.ME raised this on Page 535.Solution. Make the lifting arms 1.032" long.

Also, he 'advises' cutting a slot in the middle of frame stretcher D, 1/2" wide x 1" long." Just do it", as Guy Gibson would say.

Altogether a very nice locomotive to build.

Thanks J. Good to know you have successfully made one. Stretcher D is modified on my plans and will check out the lifting arm dimension

Richard.

Ricardo,

Yes, these sort of "errors" show up all the time. So, you get to decide what size pipe to use and how the fittings will be made to accommodate the pipe. I have made my own "standard" fittings for about four different sizes of pipe. I have made my self a chart for all the different dimensions of these fittings and also make sure I always have a physical sample of each cone and nut. This allows me to check for fit in a particular location. If you have a lathe, and just a little tooling, you will discover that it is actually quicker to make you own fittings than to order them and wait for them to arrive. I also never just make one of an item, I usually make a minimum of four each. Here's the last batch of cones and nuts I made for my loco. These were for 3/16" tube.