Thanks again for the reply. Sounds reasonable, especially given that 4130 doesn't become terribly hard anyway. The greatest hardness I have seen in any literature is Rc 52 and that was higher than all the rest at between 28 and 40 something depending upon the thickness. There is a quenching solution called "super quench" that works amazingly well on even mild steel (had to try it to believe it). In case anyone is interested, it is 5 gal of water, 5lbs of salt, 24 oz of Dawn Ultra dishsoap, and 8oz of Shaklee BasicI or 8oz of Jet Dry wetting agent (the stuff used in dishwashers to clear the spots). The formula was developed at Sandia Labs by blacksmith Rob Gunter. Apparently they were trying to not use a lye solution due to the hazards. Heat the metal to the critical temperature then quench w/constant movement. The caution is to not quench anything w/more than 30 points of carbon as it is a very severe quench. When you quench something in that solution it really squeals.
I may just experiment w/some flame hardening on my dies. I guess the worst that can happen is that I mill them again.
Thanks for the help.
Ken