leaf springs from an old bugy????

[B. Davis knives]

hey I had a guy bring me some leaf springs from and old bugy.
What kind of steel would they be,and will I have to aneal them to work them?
And what would be the heat treat temps and draw temps?

 

[Dan Zawacki]

Depending on how "old" the buggy is, it could be just about anything!

Depending on how you want to work it, yeah, softening it up will go a long way towards making grinding and machining go a lot smoother.

Before you do anything, I'd spark test it to be sure you have enough carbon to make it worth your while. If it passes that, send a nugget out to be tested. As I hear told, a bit of sleuthing around this very board will provide some links to a place that'll tell you EXACTLY what you have for something like $25. That's not a half bad deal right there!

If you really really want to play the guessing game, your eyes are a better tool. Learn to read the steel. Watch the "shadow line" as you heat it slowly, pull it out and let it cool slowly. By watching for this on the way up, you should be able to nail your temp pretty accurately, even if you don't have a number for it. Quench in a fast oil, then temper at 300 to begin with. If you got enough of the stuff, you can play around with it, temper at 300, 350, 400, etc and test them off to see where the hardness / toughness "sweet spot" is.

Just be careful with this method. It's way too easy to overheat and burn your tip. Best to hold the tip with tongs and heat the body first. Nice and slow and even, until the whole thing is in soloution. If you have very tight control, and a lot of experience, and want to try soaking at that temp, it could be helpful, but if it's a 200 year old buggy spring, odds are it isn't all that complicated of a steel.

 

[G. Shahan]

I have one leaf That came from under a wagon seat. I've been wondering how to treat it

 

[Dan Zawacki]

Again, if it doesn't have enough carbon to make a good blade you're wasting your time. The by eye method works just fine for very simple steel, which is what you're likely to be dealing with. However, if you do everything right and still turn up a peice of scrap, don't be surprised. It has a chance of being an excercise in frustration.

The problem really is twofold. The elastic property of steel that allows it to be useful for springs isn't effected by a noticeable amount by alloying or HT. As long as the spring isn't asked to deform to failure, where permanent bending or breakage could occur. Thus, with the springs from a really old wagon or buggy, it's purely guesswork. Sure, it could be something really cool and full of carbon that will harden up beautifully and cut for a long time. Alternatively, it could be mid to low carbon, barely hardenable, and still be useful for some tyoes of springs, but practically useless for blades.

If you are dead set on recycling old steel from an unknown source, use it for guards, bolsters, etc. Or practice a new grinding or shaping procedure so when you're working with the good stuff, you'll know what your doing. Failing that, getting it tested is a really good idea.