Something Like Babbitt

[PolskiFran]

A friend of mine showed me an old model steam engine he had picked up at a junk yard. It was apparently home made. The cylinder, steam chest, cover, and flywheel were cast from a material that was babbitt-like. There was a material like this used for making castings for toys back in the early 1900's. I have heard the name before but cannot remember it. The engine is dated "1902"

Any info would be appreciated,
Frank

 

[cfellows]

Could it be ZAMAC? Also called pot metal? Basically an alloy of aluminum and zinc with a small percentage of a few other things thrown in...

Chuck

 

[Circlip]

It was called MAZAC on this side of the pond, car door handles and trim castings on cars, you could always tell it from propper metal as it was chromed and in very short order it would be pitted and the chrome flaking off. Its derogatory name was "Monkey metal" Ian.

 

[Bogstandard]

A lot of parts on my 70 year old Atlas lathe are made of Mazak.

All the change gears, pullies, handles, main gears on the head, etc.

Most of them are still like new. So it is very hard wearing if in the right context.

John

 

[cfellows]

Pot Metal got a bad name in the US because a lot of the parts were cast with very thin sections, using ribs for reinforcement where necessary. Unfortunately, the alloy is brittle in thin sections and breaks easily.

When cast in thicker sections, it's quite strong, easy to machine, and, at .218 lbs/cu in, is almost as heavy as cast iron (.284 lbs/cu in. It melts at about 700-800 degrees fahrenheit, so is well within the range of the home metal caster's abilities. I've cast flywheels and other small engine parts with it with considerable success. I mix about 12% aluminum with 88% zinc.

Chuck

 

[Circlip]

Thanks for the "K" correction John, Yes, in the thirties we were making things to last, :big: We STILL had an Empire then :big: It took a second World war for us to realise we had to make things faster and cheaper to the detriment of quality, Having said that, how many Electron castings were used in the racing motor cycle industries : Ian

 

[PolskiFran]

Thanks for the help. I don't think it is Zamac, it seems to be softer. It does seem to be a good deal softer than the material used in the gears on my Atlas lathe. It does have the same "finger nail scratch test" qualities as babbitt. I have been comparing with some old "Slush Cast" toys, but that doesn't come close either.

Frank