On Sat, 11 May 2013 15:02:17 -0700 (PDT), Ivan Vegvary
wrote:

Replaced the door hinge assemblies in SWMBO's oven (purchased oven used). Made big difference. No longer need to push chair against oven door.

Questions about springs. These are 8" long, 1/2 inch diameter, 1.25 inches elongation when in use.

My understanding from my 'strength of materials' classes 50+ years ago is that metal does not deform until you reach the elastic limit. I would guess that most springs in normal use NEVER reach that elastic limit of metal. This would include automotive valve springs, screen door springs etc.

So how, when and why does a spring actually weaken. I need an education, all responses welcome.

Ivan Vegvary
In an oven application, due to heat. Or poor materials.