The Home Machinist!

. . . well there's yer problem right there. They haven't won any awards for journalistic and editorial integrity or veracity lately. Also, I don't think live steam should be lumped in to "model railroads". Yes they are railroads, and yes they are model, but this is a different animal altog...

In a way. The reason for doing such things could have been that this was cheaper to manufacture (and sell) and easier to adjust and maintain. For that engine's intended application the full capability and control of a Stephenson or other such valve gear may not have been an advantage.

Talk of what you "can" do makes me nervous, I don't like to think of miniature boiler methods in terms of what we can get away with. Bushings, or thickening pads, are good practice no matter what a code says. I'm with Chris on this, nothing larger than machine screw sizes in unbushed holes.

Charles, the valve spindle drive is simple crankshaft eccentric, so it appears that reversing is done by changing the path of steam before it enters the valve chests or cavities, apparently by some kind of shuttle valve arrangement, actuated by the lever you see.

Alan,
I had forgotten you provided this service, a needed and useful one, especially for those who come along and must needlessly repeat errors when struggling with the drawings of a couple of our more (ahem . . .) "respected" designers.

Jesse, this explains it pretty clearly . . .
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Pete, Keep posting here but also, if you haven't already, you should definitley check into <http://www.steamup.com/wwwboard/wwwboard.html> because unlike this board there is a 100% concetration of Ga1 Q&A from like-minded folks there. It's just coincidental that you've found a couple or three of...

What you have is an Atlas 6"/Mk2 Model 3950 made very near the end of production. It's a nominal 6" x 18" machine and everything except cast iron parts, includng a rather thin set of manual pages, should be available from Clausing Corp.

The sheets are relatively small, 3-1/2 x 26. Vacuum forming has occurred to me, a way to draw it tightly to the form with hands-off. That's a pretty simple and effective technique, if you have a way to draw a vacuum, which I don't at the moment.

Although I'm working with clear stock, it's going to be painted all over so I'm not concerned about inclusions in the plastic. I do want to leave the protective in place as far as possible because the polished surface will make for a slick paint job. It did occur to me that there might be a tendency...

This is basic heat bending. Plenty of guidelines and suggestions around the web if you do a search. Thanks Doug. Yes, I've just now done this, . . . plastic mfg's sites mostly. All of them emphasize the same thing, use of a heat strip to apply localize controlled heat. They also suggest keeping the...