In article Vk_gf.23339$q%.3454
@newssvr12.news.prodigy.com,
says...
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.

All tool steels will change to some degree when hardening.
W1 is about as bad as it gets. Following proper hardening
and tempering procedure will minimize the problem. A2 is
probably the most stable among the more common alloys, but
requires more care and higher temps to harden. O1 is pretty
forgiving and falls somewhere in the middle.

You may be able to pull this off with a little
experimentation and careful control of your hardening
process. If you're heating by eye with a torch it's going
to be tough. Are you aware of the magnet test for the
steel's transition temperature?

How hard do the parts need to be?

Ned Simmons