View Full Version : Reducing Hammer Spring Tension

March 5, 2009, 01:10 PM
OK Machinists, this one's for you. Can I draw my tempered hammer spring at a lower temperature, say 200-300ยบ to reduce tension WITHOUT making it brittle or totally trashing it? A new one is cheap enough, but there are two factors I have to consider: First is availability; these are very rare. Second is the fact that the manufacturer will not honor the warranty with any spring weaker than the one I have. FYI: this will be going back into a DAO 9mm. Any other experimenters please post. Thanx, -7-

March 5, 2009, 01:22 PM
Drawing, tempering, and reheat-treating is more complicated than you might think, IF you do it right. The metal must be heated at a specific temperature for a specific time, then cooled in a specific manner. You could easily ruin the spring. If it were me, I'd leave the stock spring alone. What gun is this? Is the trigger pull too heavy? Availability? How about Wolff springs?

Bill DeShivs
March 5, 2009, 01:36 PM
I make a lot of springs so-
Without knowing what kind of steel the spring is made of, you have no idea how to temper.
You generally make a spring weaker by tempering at a higher temperature, not lower.
This is a bad idea.

March 6, 2009, 11:53 AM
Thanks guys. At work, the only metal of any kind I ever had to draw more than once after treating was CPM-10V. For some reason our engineers were very specific about the hardness requirements for the die inserts and punches we made. I've treated, retreated, and drawn back A2, D2, 01, A6, S7, carbide, and especially CPM more than any other, but have never had to SOFTEN any kind of metal--much less a spring. It is in a Kel-tec, and there are no lesser springs designated for it less than 8.5 lbs. (however that's measured). After my polishing was completed, I knew I could get this little gun as slick as any other if I could just get a couple of pounds of tension off of that hammer spring. Any other ideas? -7-

March 6, 2009, 12:14 PM
Unless your Kel-Tec is just a play gun, I would not modify any of the factory parts. You can go to the Kel-Tec users forum - http://www.ktog.org/ - and see if anybody has addressed this modification.

Kel-Tec parts are inexpensive and their customer service is fantastic

chris in va
March 6, 2009, 05:17 PM
It is in a Kel-tec, and there are no lesser springs designated for it less than 8.5 lbs

Oh, why didn't you just say it was a KelTec?

Easy mod to reduce trigger pull force. Involves a nail, believe it or not. Works pretty well actually.