After heat treating die - shrink or expand?

[bigjake]

My point forming die's ID is about 1.5 thou too large, when heat treating, does the bore generally shrink or expand? the die is an un-drilled die blank I ordered from pacific tool & gauge. I believe Its 4140 steel, im not sure, the site says to heat to 1650-1700 deg. F and let cool slowly.

thanks

[clodhopper]

My limited experience with O-6 graphmo is, the the hole measures larger after heat treat.
Quenched and tempered.

[bigjake]

Great another one bites the dust.

[M.A.D]

What were you trying to make?

[Gew]

If it .310 or .312 you can make a bullet sizer to bring it back to .308.

[bigjake]

If it .310 or .312 you can make a bullet sizer to bring it back to .308.

brass spring back? unless i bond the cores.

[Faret]

Depends on how you heat it! Torch from the outside it will shrink. Heated slowly in a oven it will get bigger. Just my experience!

[john.k]

Depends on the type of steel too.......if distortion is an issue ,the correct steel can be heat treated by a commercial shop to max hardness with zero distortion......two simple methods for home shop are use a prehard steel ,or a precipitation hardening steel,not needing a high temp to harden.