Should I temper home made springs?

[blockmanjohn]

Hi, I am winding the springs for my 1/4 Galloway from music wire. I read some place that after winding they should be tempered by placing them in an oven at 450 degrees for 3 or 4 hours. Has any one else used this method? My big question is, if the springs need to be tempered, should they be quickly quenched after the heating period is over, or should they be left to cool slowly at room temperature? This may not be a big deal one way or the other, but I would like to get it right the first time. Thanks, John.

 

[Baner]

To be pedantic the oven bake is for 'stress relief' rather than 'tempering'. There is various charts to be found regarding stress relieving springs; I'd post links but there seems to be a spam filter blocking posts with links. There's a bit of variance in the charts but generally you need to go to 500 degrees F for an hour then leave them in the oven to cool slowly.
Personally I've made small springs around 20swg and smaller and I've never bothered to stress relieve them and haven't had any failures. Then again they haven't been for stressful applications, so your results may vary.
Dave.

 

[WOB]

I agree. I've made a lot of valve and gun springs over the years, most of .040" wire or smaller and have never stress relieved them. No failures. Larger wire and tighter bending radii might benefit from stress relieving. but I have not needed it.

WOB

 

[mayhugh1]

I always stress relieve mine, but most don't bother and don't notice any issues. What happens is that the springs will weaken quicker over time as they're exercised if they aren't stress relieved. I once made some measurements and saw 20%-30% loss in spring force almost immediately without the stress relief. The heat treatment gives the wire a set in its new configuration as a spring.
I used to participate in competitive pin shooting at a local gun range using a heavily modifid (1911 style) 45 for which I was winding my own springs. Until I learned about stress relieving them, freshly wound sprig would last only a few matches. They weren't breaking - just weakening to the point where they weren't providing any advantage. - Terry

 

[Baner]

What method do you use to stress relieve springs Terry? The info I posted is only what I gleaned from charts, not actual experience. I'd be interested to know what temps and times you've had success with.
Thanks.
Dave.

 

[Brian Rupnow]

The truth---Yes, you should bake them in an oven at 350 to 400 degrees for a couple of hours to "set" the temper in them. Reality---At the scale we work at, it doesn't make any real difference. If the spring was for a piece of production machinery that cycles thousands and thousands of times, the springs would gradually collapse and not do the job they were intended to. For us, (and I've tried both tempered and untempered springs) it makes very little difference.----Brian

 

[mayhugh1]

Dave,
See post #215 here:

https://www.homemodelenginemachinist.com/threads/quarter-scale-merlin-v-12.24153/page-11

Terry

What method do you use to stress relieve springs Terry? The info I posted is only what I gleaned from charts, not actual experience. I'd be interested to know what temps and times you've had success with.
Thanks.
Dave.

 

[Baner]

Wow! Heaps of spring information there. Thanks Terry.
Dave.

 

[Cogsy]

There is various charts to be found regarding stress relieving springs; I'd post links but there seems to be a spam filter blocking posts with links.

I don't know what the criteria is set to, but there is a new feature flagging some posts with links for approval. I clear it out (and approve the non-spam posts) whenever I'm online, which is most days, but there will be some lag between posting and it appearing sometimes.