What's a good material for molding internal threads which can be unscrewed so the pitch diameter can be checked with thread measuring wires which will work on both metal and plastic?
I'm thinking a fusible alloy (bizmuth, etc) and know it will work on the zinc die cast parts to be checked but no so sure about the glass filled nylon parts.
I'm working on a set of unscrewing cores for a used mold which was made somewhere else and have no history on the tool so I'm to work steel safe and tweak it in a later date. I'd much prefer to work to numbers I can measure than the wild ass guesses the halfwit (OK, they're not really halfwits, they're just stoned half the time) moldmakers on the job expect me to make based on how the parts fit on a socket head cap screw. Feh.