Much of machine parts came from a wood patern...tested and then made of metal ...
Tragedy of our JR HS / HS Industrial Arts build-out, tail end of the 1950's South Hills of Pittsburgh - where they "know about this s**t", was that the damned fool Archeotick put the Chem lab right over the shop where we shudda had ignorant open air!
Nice powerful forced-air forge furnace with a nat gas pipe the size of a sewer line as had been installed could not be USED!
Sooo.. we got the course on patternmaking, leather pre-form off a store-bought roll for radiusing inside corners, as well as wood, (those were "pre-bondo" days if yah recall). Made up our patterns, "pounded the drag" of genuine Michigan green...
Then got "eyeball" graded on the sand by an experienced instructor... but never got to pour even an OUNCE of ACTUAL Iron!
Only things we cast were lead deadblow hammer heads off the smaller furnaces, and those were the standard "kit" with handles and molds.
Seeing what Denis Foster and others on PM have managed to do on slender resources?
We surely cudda done ZAMAK, shiney-wood or even Bronze in smaller items. Several of us DID do, one classmate in 22 K Gold (mind, he was a dentist's son!) .. but all of that to-home, not at school.
Must have been the damned Liability Lawsters as prevented our Skewl from "finding a way"?