Leaf Spring Losing Its Arch?

[Luv2rideWV]

Here is a question about leaf springs: I have a S&W revolver that had the main spring arched in order to reduce the trigger pull. After a year or so, I disassemble the gun, and upon reassembly the trigger pull seems a tiny bit heavier. Nothing was changed that would/could affect trigger pull. THEREFORE, CAN A LEAF SPRING (MAIN SPRING) LOSE SOME OF ITS ARCH WHEN IT IS REMOVED FROM THE REVOLVER?

[toothguy]

Just speculating, the strain screw might not have been fully seated before removal and now is.

[bountyhunter]

Just speculating, the strain screw might not have been fully seated before removal and now is.

That is what has to be the cause, because you said:

"After a year or so, I disassemble the gun, and upon reassembly the trigger pull seems a tiny bit heavier."

If the spring was losing some of it's bend, the trigger pull would get lighter not heavier. I always set up my leaf springs so that I get the spring force I want with the strain screw about 1/4 turn out from all the way in so that I have a little extra spring available in case I get some ammo with stiff primers that are not wanting to fire. I use blue Loctite to set the screw where I want i to get the right spring force.

Of course purists cringe at bending springs and running the strain screw out to adjust the spring force so proceed with caution...

[Luv2rideWV]

Nope, I cranked the strain screw down tightly both times.

As for the leaf spring used as the main spring in a revolver, if you bend the spring to give it more of a curve, you are reducing the trigger pull. If you straighten that spring out some, you are increasing the trigger pull. So the bountybunter may be a little backwards on his assumptions regarding increasing or decreasing the trigger pull by bending springs.

I was actually asking a question about whether, or not, a leaf spring can lose some of its arch when it is no longer under compression. Instead, everyone wants to tell me it is the strain screw. I had previously asked this question in the revolver forum, too.

The question is: Can a leaf spring lose some of its arch when it is no longer under compression?

[Steve RA]

I wouldn't think so, but I'm no spring engineer.

[bountyhunter]

I was actually asking a question about whether, or not, a leaf spring can lose some of its arch when it is no longer under compression. Instead, everyone wants to tell me it is the strain screw. I had previously asked this question in the revolver forum, too.

The question is: Can a leaf spring lose some of its arch when it is no longer under compression?

The answer is NO.

Nope, I cranked the strain screw down tightly both times.

As for the leaf spring used as the main spring in a revolver, if you bend the spring to give it more of a curve, you are reducing the trigger pull. If you straighten that spring out some, you are increasing the trigger pull. So the bountybunter may be a little backwards on his assumptions regarding increasing or decreasing the trigger pull by bending springs.

Really.... OK: leaf springs come from the factory with a specific bend (arch). Gunsmiths increase the curve of the arch to reduce trigger pull. Then, you install it and crank down the strain screw which arches it even more. My point was that if the spring steel was "taking a set under strain" as mechanical engineers would say, you would lose some spring force and get a lighter DA pull, never heavier pull. The spring would also have slightly more arch "at rest" than it originally did.

There is no effect that can cause a leaf spring to "straighten" itself out sitting on the bench and cause a heavier trigger pull.

Edited July 17, 2014 by bountyhunter

[Luv2rideWV]

Thank you all for the assistance.

[peterthefish]

Did you loctite in the sprain screw last time you assembled the gun? If not, it likely backed gradually out over the course of the last year causing an increasingly lighter pull that you noticed on reassembly. It's happened to me before.