Just so I understand:
1) It comes out of the hardening quench with a little warp to it.
2) You clamp it to something straight (the big file), maybe shimming to over-compensate a little.
3) You temper it at the same temp and for the same time you'd temper it if it weren't warped.
Jeez. I had a blade I took through the whole damned heat/beat/normalize/anneal/harden/temper process three times before it straightened the way I wanted it to. Good thing I haven't warped one since then...now that you've made correcting it look so simple.