Quote:
Originally Posted by Philliphastings
Some years ago an associate showed me some steel moulds for Australian track which he had squirrelled away. from memory they were steel and box shaped with an upper and lower half which bore the impression of a single track link at a time.
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Hi Phill,
Interesting info. Since Wayne's pics show aluminium patterns that already have the little markings (mentioned and/or displayed by Ron and others earlier in this thread) cast into them, it indicates that they were cast from a pattern higher up the evolutionary tree so-to-speak. Presumably even aluminium patterns would be worn away from repeated use (ramming molding sand against them) then they would need to be replaced once certain tolerances were exceeded. So it's likely that they were poured using aluminium into a metal mold of a higher melting point - in this case steel or possibly cast iron. Since the marking plates wouldn't have been screwed to a (female) mold it indicates that the mold you describe was cast from a master pattern even higher up the chain.
During the war in aircraft plants, the hammers and dies bolted into Drop Hammers (for stamping aluminium alloy sheet obviously) were poured from lead for one and an alloy of lead and something else - tin or zinc that bore a tradename I can't think of at present. The reason for the two was that one had a slightly lower melting point and could be poured into the other to create the reverse shape without damaging it. It was a relatively quick method and reasonably easy metals to work. It lasted long enough and then melt the stuff down again and pour out a new hammer and die.
Perhaps Wayne could send thru some pics of the other bits he mentioned?
Regards
Alex