Plastow will sell individual drawings.

Though I would have thought someone like Western Steam would have made the 3" boiler before so may have the drawings on file or at least give you a ball park figure. It's going to be in excess of £2K I would think.

I was thinking it was a bit simpler to make than the usual TE boiler as there is not the usual firebox, although it is a 3"/ft engine the full size was not large so the boiler won't be as big as say a 3£ road loco

Engineering In Miniature ran a build of the Robey No4 2" scale from January 1995 and a quick glance in the March of 1995 I found a drawing of the boiler for it. I have not been through all of mine so can't say when it ended

Derek you have a PM with a couple of ideas

Stainless is usual for the two rods, most of the etc would need clarification as to what part it is but unlikely to need stainless

Not prototypical, but I am using 303 stainless steel for piston and valve rods, and associated nuts, on my 4" scale Burrells. Piston rods and nuts on the right, external threads are screwcut to ensure proper alignment:

Andrew

In my experience 303 machines beautifully. For standard threads I use full form inserts, and they work very well on 303. The threads on the piston rods are 3/8" 32tpi Whitworth. I also find that 316 machines well, but 304 is a pig for some reason. According to a recent thread on Practical Machinist even the professionals hate it.

Andrew