[SEL] Tap & Die Set Help Needed--OT

[Curt]

Reg,
I don't think trying to cast this kind of detail would be cost 
effective. Can you imagine the corebox work required to cast threads?! 
And then hoping for this kind of detail duplication when pouring is 
wishful thinking.
Besides, casting materials with the highest shrinkages wouldn't generate 
shrink near 1/32". For example aluminum would have a shrink rate of .015 
per inch. Consider a 1/2" bolt. This would only need to be cast .007 
large so a 1/32 (.031) oversize wouldn't be appropriate.
My vote is with the fellows that speculated on oversized threads for 
repairs. As old as the die set is, this is pre-heli coil days.
Curt Holland

R & M Ingold wrote:

> Ive been thinking on this and it crosses my mind that patterns are 
> made oversize to allow for shrinkage. Could these be made for pattern 
> makers? Just a thought.
> Reg & Marg Ingold.
> Newcastle, NSW, Australia.