tail spring re-arch

[avidflyer]

I think he was referring to a press that uses a bottle jack for the power source. I have a 20 ton press like this from Harbor Freight, and have used it to rearch tail springs. Works great. Jim Chuk

[jiott]

So apparently you guys just overbend the spring in a press until it takes a permanent set at the new arch. Do you not heat first and then heat again after and quench, etc.? I didn't know you could cold bend them to a new shape without damage.

[SkyPirate]

Jim the springs used for tail wheels now a days are made from what is called "Blue Tempered Spring Steel" its not the true high carbon spring steel still used in trucks etc ,..don't heat it you will activate the atoms burning off what carbon is in it making it soft,,if you quench it it will become brittle

added: its better to bend a tail wheel spring then break it,..same with most of the light duty trailer springs,..they will bend before they break on most newer applications

[avidflyer]

You bend the spring cold. Unless you know how to retemper spring steel to the right amount. I know the spring shop I talked to bends theirs cold as well. Another point of interest, if you are making up a new spring and need to drill holes, don't drill a pilot hole and then try to drill the right size larger hole. Drilling the spring work hardens it and you probably won't be able to drill the larger second hole. That advice also came from the spring shop. I didn't try to prove them wrong. It's best to use a drill press so you can drill at a slower speed with plenty of pressure, maybe use some cutting oil as well. I would use a new sharp drill bit as well. If you don't make it through in the first attempt, the second try will probably be worse. Jim Chuk

[SkyPirate]

very true Jim, drilling it does the same heats it up work hardening it which will also make it brittle at the sides of the hole , when I use to extend a tractor trailer frame or add a frame rail I used a magnetic drill with a low RPM drive ..it would take 20 minutes to drill a 1/4" thick wall no fluid..just sharp slow turning bit

[n85ae]

I've had no troubles drilling holes in leaf springs, just takes cutting lube, a
sharp bit and pressure. I drilled mine last year with my drill press, no problems
at all. I always drill a pilot hole, and work my way up in sizes until the final
size is achieved.

Jeff

[SkyPirate]

Musta been the new lower carbon Blue Tempered Spring Steel

[jiott]

Is there a good way to tell if its the "Blue tempered spring steel" or the old "Hi carbon spring steel"?

[charliehill]

here is the source of spark test from WIKIPEDIA.
https://en.wikipedia.org/wiki/Spark_testing
http://www.ylflux.com/