The Home Machinist!

Beautiful job! I estimate I had 8,000 hours in my Northern, which looks nowhere near as detailed! BN

Perhaps there is something forgotten in the original post. If you have the co effecients of expansion of copper and steel and you have the length of the boiler and tubes between the inside surfaces of the flu plates do the math and find out just how much difference there is in expansion at a given ...

Keith, I'm speaking of concepts here, not absolutes! To say that rails do kink occasionally is a distraction from the point that 99+% of the time, the rails are held in place by the track anchors, ties and roadbed. If this wasn't true, the railroads certainly wouldn't use welded rail, because they ...

Maybe the tube sheets flex outward enough for the length increase to not show itself in any detremental way. Could be. I would be concerned though if tube sheets were that weak. Maybe the tubes push out of the tube sheet a tiny amount, but again it so slight as to not show itself. It seems then tha...

Anyone with a bit of care & savvy can transfer liquefied gas from one cylinder to another. The stuff is liquid , remember, and liquids pour like, well,..... liquids. A tank of propane elevated higher than the "empty" will drain down by gravity into a tank lower by some feet, the greate...

Seems to me that resolution of the issue brought forth in this thread, that is, that "stainless steel is a poor conductor of heat", is missing the simple point that all metals conduct heat, to one degree or another. Copper simply does so better than stainless steel. BETTER, that's all. I c...

Well spoken Fred! The tubes do not buckle or anything like that, they just take up the strain internally and the stress is not enough to cause buckling they probably swell a miniscule amount and the outward stress probably helps them seal. I have put copper tubes in more than a dozen boilers withou...

gwrdriver wrote:Technically, if a model boiler has a leak it won't hold pressure and it can't pass the hydro can it.

Good point! But is it possible for no leakage to be detected by pressure drop during cold hydro testing, while under heat and steam pressure, a leak might then show up? BN

This could result in a "hot-seat"! BN

A few more of my unending questions, if no one minds! With a coefficient of linear expansion of about 10 for copper vs. 7 for steel, assuming uniform temperature rise of flues and shell, the tubes should increase length roughly 40% MORE than the shell. Often, the tube ends are procerred (if spelled ...

Does a concensus exist regarding slight boiler leaks? Seems I have seen both prototype as well as scale models belching steam from all angles sometimes!

Should boilers be absolutely leak-tight? I lean towards a "yes", myself, but really don't know! BN

Not sure I understand the concept of "tapered bolts" completely. The unthreaded shank being tapered? If that, then the part being clamped by the bolt would have no clearance within the hole, thus preventing movement. In the metal stamping industry, relative movement between joined parts is...