Blued Steel Hairsprings for watches and clocks

by Bruce Forman
(234 Eagle Ridge Drive, Valparaiso, IN)

I am looking for information on the manufacturing techniques used to make blued steel hairsprings (carbon steel) for clocks and watches. These type of fully hardened springs do not appear to have been made in recent years owing to the the use of more modern alloys that do not rust.

Any old timers remember how it was done? Would be interested in any practical or historical information on this subject,also any antique equipment related to same or pictures.