Flat springs are different???

[JohnKSa]

It is accepted that deforming a spring (stretching or compressing it to the point that it loses its original shape) will ruin the spring. It reduces its lifetime and permanently weakens it.

However, I just read an article in which a respected gun writer advised bending the legs on the Colt 1911 sear spring to tune it. He does advise that "constant bending will weaken it." but my understanding is that anytime you bend a spring you've weakened it.

Are flat springs different from coil springs in this respect?

 

[Tommy Vercetti]

that's a good question, I've heard that before but I've never tried it

 

[Bill DeShivs]

Generally, it is not good practice to bend a leaf spring after heat treatment.
However, it can be done. Bending a spring past it's elastic limit does not actually weaken it, but it does change the characteristics.

 

[JohnKSa]

Bending a spring past it's elastic limit does not actually weaken it, but it does change the characteristics.

Could you elaborate on this? It is my understanding that bending any metal object past its elastic limit results in the object being weakened.

 

[Bill DeShivs]

John
It's hard to explain, not being a metallurgist-type. If a spring is bent past it's elastic limit it will not return to the same position, but the spring does not actually lose strength. The "throw" of the spring simply changes. Same with car leaf springs-if you overload them they will not return to specs, but they are still springs. They just don't work well for their intended purpose.

 

[Casimer]

I think that a leaf spring has a deflection tolerance in the same way that a coil spring has a compression and extension tolerance ( i.e. elastic limits). The leaf springs in a 1911 sear spring aren't typically kinked or deformed significantly when adjusting their weight.

I've encountered a few leaf revolver mainsprings that have been kinked deliberately, usually at about the lower third of the spring. This seems to create a compound spring. I'm guessing that the intention is to reduce the pull weight and perhaps make its distribution more consistent.