I have been doing heat treatment of peoples' blades for several years now. I can heat treat the most popular steels such as O1, D2, Niolox, N690, Damsteel and a few more. If you have a blade steel not on the list, ask me and I can tell you if I can do it or not. I can also do folder springs as well in a variety of steels.
The heating is done in my digitally controlled Evenheat oven and quenched in liquid nitrogen if the steel needs it. The cost is £11 per blade for oil hardening steels like O1 and £12 for air hardening steels like N690. The prices are for blades up to 300mm long and 6mm thick. Please ask for quotes for longer and/or thicker blades. The cost includes signed for return UK postage. The service also includes straightening the blades post hardening, a service few large commercial firms can offer. Turnaround time is typically 3 weeks or less.
Please contact me for further information.
Disclaimer: I am not responsible for loss or damage to blades/springs sent to me for treatment.