Post by warthogge on Jun 10, 2019 22:36:03 GMT -5
Hello everyone,
Over the years I've read quite a few posts on springs and recommendations how to ease their 'stiffness' when new and/or when they should be considered for replacement. Some of the comments I have difficulty buying into, particularly one regarding new recoil springs, locking the slide back and leaving it that way for several days or more to reduce resistance when racking the slide.
I question whether that really works.
It is my understanding that when a load (stress) is applied to a piece of metal it first deflects elastically and if the load is high enough, it will deflect plastically:
• Elastic deflection is when after removing the load on the steel, it returns (springs back) to its previous shape/geometry.
• Plastic deflection is when the material is loaded to a point that exceeds its elasticity, permanently deforms and after unloading does not return to its previous geometry.
Engineers design springs to not exceed their elastic capacity in normal operation they were intended for. However, we do know that recoil springs, over many cycles (loadings) do get shorter. I asked some of my metallurgist friends about this and they replied that at stress below the yield strength of the material (where deflection crosses over from elastic to plastic) a very slow plastic deformation takes place (creep) and the spring loses length. How much creep depends on the temperature, the stress in the metal, the metal's yield strength and the time. In particular, increased temperature, stress and time increases creep. So, heating the spring up during a range session will increase creep and the spring will lose length.
So, it is my conclusion that:
Your thoughts?
Over the years I've read quite a few posts on springs and recommendations how to ease their 'stiffness' when new and/or when they should be considered for replacement. Some of the comments I have difficulty buying into, particularly one regarding new recoil springs, locking the slide back and leaving it that way for several days or more to reduce resistance when racking the slide.
I question whether that really works.
It is my understanding that when a load (stress) is applied to a piece of metal it first deflects elastically and if the load is high enough, it will deflect plastically:
• Elastic deflection is when after removing the load on the steel, it returns (springs back) to its previous shape/geometry.
• Plastic deflection is when the material is loaded to a point that exceeds its elasticity, permanently deforms and after unloading does not return to its previous geometry.
Engineers design springs to not exceed their elastic capacity in normal operation they were intended for. However, we do know that recoil springs, over many cycles (loadings) do get shorter. I asked some of my metallurgist friends about this and they replied that at stress below the yield strength of the material (where deflection crosses over from elastic to plastic) a very slow plastic deformation takes place (creep) and the spring loses length. How much creep depends on the temperature, the stress in the metal, the metal's yield strength and the time. In particular, increased temperature, stress and time increases creep. So, heating the spring up during a range session will increase creep and the spring will lose length.
So, it is my conclusion that:
- If I want to reduce the load in a new spring, I need to shoot it; locking the slide back and leaving it in my safe for a few days won't work.
- If I buy a used gun and don't know its history, I should go ahead and replace all springs so I know what I am working with. After all, a spring set is not that expensive and it gives me the opportunity to fully look over the gun and give it a thorough cleaning.
- Or, if I have a reference length for a spring of same design (design strength, number of coils, wire diameter, etc.) I can use that to determine whether I need to replace.
Your thoughts?