Dick, thank you for the info. In searching the news letters I found the attached heat treating receipt from 1979 in the NL 56. It differs a bit from your spec but I think I am learning that the heat treating process is a heat, quench and temper process to achieve 180000 psi tensile strength without leaving the 4130 in a martensite structure. I guess a good heat treater will be able to tailor their process to achieve that strength.
I live in the St.Louis, Missouri area and it looks like there are a few heat treaters to contact. I have not found any spring repair outfits around here yet. It looks like the fellow Mike Fleming who started this thread lives in this area, I have sent him a PM but no reply yet. Would any of you know another way to contact Mike. I would like to pick his brain on the heat treaters in this area.
thanks for the help
Dave
![Image](http://s2.postimg.org/6xecq3xf9/Heat_Treat_Receipt_Page_1.jpg)