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Weakening a Flat Trigger Spring

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22 August 2007, 00:26
Michael Robinson
Weakening a Flat Trigger Spring
I have a rifle with a flat trigger spring and a slick but 7 lb. pull. The trigger and sear bearing surfaces have been stoned, so the too strong spring is what seems to be at fault.

In several of my S&W revolvers, the flat trigger springs were weakened by the late and great Fred Sadowski by filing both sides down and narrowing them, which resulted in very smooth DA pulls.

Is that the best way to do it? Any advice will be much appreciated.


Mike

Wilderness is my cathedral, and hunting is my prayer.
22 August 2007, 03:16
Alberta Canuck
quote:
Originally posted by mrlexma:

... the flat trigger springs were weakened by the late and great Fred Sadowski by filing both sides down and narrowing them, which resulted in very smooth DA pulls.

Is that the best way to do it? Any advice will be much appreciated.



That's certainly how I would do it, if it was my rifle and I couldn't just buy a commercially-made lighter poundage spring.

If you have a very fine grit grinding wheel and are VERY careful to proceed slowly, and not to overheat the spring while grinding it, that might work even better for you. It is also possible to taper the thickness of the spring but is much more "chancey" too. I wouldn't suggest trying to alter the thickness.

Another point to remember is when you narrow the width of the spring, do not leave ANY square corners where you have filed or ground material away. Rounding them with a fairly large radius at those places helps avoid early breakage.
22 August 2007, 07:27
Michael Robinson
Thanks, AC, for the good advice. No commercial replacement can be had. I will take it slow and easy on the sides and leave no sharp edges.


Mike

Wilderness is my cathedral, and hunting is my prayer.
22 August 2007, 09:59
tnekkcc
There is a tapered flat spring in a 91/30 that acts as:
1) trigger spring
2) sear
3) bolt release


I narrowed one to make it lighter.
It broke after some use.
Had I narrowed with the correct taper and not left any micro notch stress risers in it, it would still be o.k.

It is not easy to narrow a flat spring.
22 August 2007, 11:50
Mark
If you use a grinder, a good technique to use is have a pot of water that you dip the spring into, and then grind it while it is wet. Stop and re-dip the second the water starts bubbling.

This will prevent it from losing any temper, no matter how much grinding you do to it. Just remember to dip it the instant you see the water bubbling, not a half second later!


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