"Siggy" wrote in message
m...
I made several tight toleranced parts yesterday. All of them about .2800"
round with a number of different diameter steps that call for tolerances
down to .0003. I made them from W-1 drill rod. The parts turned out
nicely
with all fits and tolerances just right. Then I hardened them...

Problem is that after hardening, the diameter of the parts increased
anywhere from .0005 to .0007. Of course, they are now unusable. I
hardened
them by heating to bright red then quenching in water.

I'm wondering what I can do the next time to avoid this problem? Could it
be that I heated the part too hot before quenching? Does W-1 always have
this problem and/or is there a better steel to use? Thanks for all
suggestions.

Robert

Hardening carbon steel converts the phase to martensite, which is less dense
than the unhardened phases (ferrite, mostly). Thus, it expands when you
harden it.

Usually such precision parts are turned, hardened, and then ground. In a
hobby shop, they may be lapped after hardening, rather than ground.

--
Ed Huntress