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Rebending leaf springs

DPittman

DPittman

Ultra Member
Any experts here on rebending leaf springs? I am wanting to straighten out a small end portion of a leaf with out causing damage. I just need to flaten out the curved and "machined" length (2.75")then drill a hole thru the stuff for a mounting bolt.
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In my experience with main springs for antique firearms, if you bend without heating to the point that it retains a new form, there will be cracks in the spring that will almost immediately fail in use...in other words anneal then bend, then re-heat treat, then re-temper.
ohh ya...drill your hole in the annealed state.
Brownells sells flat spring stock (a local gunsmith may have a selection close by...Stel...) in its annealed state that you can make your own new spring from , comes with "how to torch heat treat" directions that most home shop gunsmiths will use because of equipment limitations.
 
historicalarms said:
In my experience with main springs for antique firearms, if you bend without heating to the point that it retains a new form, there will be cracks in the spring that will almost immediately fail in use...in other words anneal then bend, then re-heat treat, then re-temper.
ohh ya...drill your hole in the annealed state.
Brownells sells flat spring stock (a local gunsmith may have a selection close by...Stel...) in its annealed state that you can make your own new spring from , comes with "how to torch heat treat" directions that most home shop gunsmiths will use because of equipment limitations.
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That's not what I wanted to hear. I need to drill both ends of the spring and only straighten the one end a bit. Maybe I will have to anneal both ends and leave them in that state. I think the leaf is heavy enough material that it should not likely fail ( I hope and guess) .
 
Ya, id just drill the hole with carbide and shim the spring to the right geometry.

I haven't seen @Darren around in a while. But I recall that he played with big springs. Maybe reach out to him and tell him that his hobby metal working friends miss him.
 
DPittman said:
Any experts here on rebending leaf springs? I am wanting to straighten out a small end portion of a leaf with out causing damage. I just need to flaten out the curved and "machined" length (2.75")then drill a hole thru the stuff for a mounting bolt.
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Click to expand...
I'd be tempted to to support it in 2 places on each side of where you want it to flatten and apply hydraulic press between the two points with significant vigor? Cautiously a bit at a time. Many many moons ago I recurved a model A ford spring to the oposite curve so the spring eyes turned up instead of down. No press just a big sledge hammer.
 
Don Sipes said:
I'd be tempted to to support it in 2 places on each side of where you want it to flatten and apply hydraulic press between the two points with significant vigor? Cautiously a bit at a time. Many many moons ago I recurved a model A ford spring to the oposite curve so the spring eyes turned up instead of down. No press just a big sledge hammer.
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Yes I've considered that as I have easy access to a hydraulic press. I may have to flaten out the curve on the other end also but I'm still figuring out things. Thanks for the input folks.
 
Don Sipes said:
I'd be tempted to to support it in 2 places on each side of where you want it to flatten and apply hydraulic press between the two points with significant vigor? Cautiously a bit at a time. Many many moons ago I recurved a model A ford spring to the oposite curve so the spring eyes turned up instead of down. No press just a big sledge hammer.
Click to expand...

You know, I’ve done that too many many moons ago as a young and green guy but I didn’t want to mention it because I thought it too shade tree/brute force.

The rest of the story: I was shown the trick by a very experienced mechanic to reduce the arch of the leaf springs of a race car. I said no way that would work and he proceeded to show me you could do it. Just set the leaf across a couple of bars welded to a chunk of channel and thump it with a 10 lb sledge. Keep moving along the spring until it looks about right. Careful with your hands while holding onto it!

At the time I didn’t believe that you could (permanently) bend a leaf without breaking it. I never had a problem with any of the leaves I re-arched.

That said, for something as critical as a tail spring on a plane I’m less inclined to do something like that.

With it bolted, does the spring bottom on the mount bracket or is there still a gap (arch) under it where it clamps to the mount? If there is I’d be tempted to make a curved shim that gives you the right angle of the spring and allows a length of it to be clamped between the bolt and the mount without a gap. Avoids trying to bend the spring on that end at least.

Maybe something similar at the other end too?

D 😎
 
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