I have a collection of old spring leaves and also some new spring leaves and I need some insight into what the best options are.

1. Is it safe to mix old and new spring leaves or will the old ones be work hardened and brittle and more likely to break?

2. What is the best way to recurve the leaves - I have some that are too flat and others that are too curved. I'm guessing that they should not be heated.

3. When shorteneing leaves, it is a lot less work to just trim and shape one end but this means that the center hole will need redrilling in the new center location. Is the old hole going to form a stress raiser and be more likely to brfeak at this point? Or should I keep the hole in the center and cut both ends and shape them?

4.I need to weld new "washers" on the outer ends of the longest spring in each pair for the connecting bolt from the lower spring to go through, and also need to build up the transition to the disc on the sides with weld. I can let the welds air cool but is the heat of the weld going to affect the hardening of the steel. As the next leaf up is full length and extends to the bolt centerline, I'm thinking that this may not matter?

5. Are the nuts on the bolts connecting the two halves of the ellipse together held fast by just rivetting over the end of the bolt or is there some other system used.

Any hints and tips greatly appreciated as always.

Thanks

Jeff

It is safe to mix good used leaf springs and new leaf springs as long as they all have the same arch.
To re-arch springs, a spring business is the best person to have it done at. The Model A Ford springs can be re-arched in a vise using a large hammer but their spring quality must be a lot different than a Stanley's. If you were to reheat leaf springs, you would remove the temper and they could become very brittle. I have found that air cooling is too fast and that will make leaf spring steel brittle. It is a real science to set the temper in leaf springs.
The center bolt hole should be retained in the center of the spring. To have one located elsewhere in the spring stack is inviting a broken leaf at that bolt hole.
To weld on the ends of the spring, it would be prudent to present the washers to the spring shop and let them weld on and also control the heat on the spring. If I was to weld replacement washers, I would use my mig welder and continually keep the leaf spring cool to retain it's temper. If the spring did get hot, a slow cool in a bag of insulation would be prudent. The lower spring isn't as big of a risk for losing its temper and that should be an easy one to weld up. Just keep the spring cool all of the time.
The nuts on the spring end connecing bolts are lightly peened over to keep them from accidentally backing off.