Leaf spring cracks?

J

jkf96a

Well-Known Member
Was forging on a piece of leaf spring from a '58 Ford last night. I started with a piece cut about 3/4" wide that tapered from 1/4 down to 5/32 or so. I forged a preform tip on the tapered end, then started working on my bevels. I noticed about that point that there were some cracks in the steel. Some came from each edge toward the middle of the piece, and others seemed to run along the axis of the piece without ever contacting the edge.

I had used this piece of steel heated to 1200 to warm my quench oil about three times.

The question is this: are the cracks the result of my sub-critical quenching, of the way I was forging the metal, or were they cracks in the original leaf spring? There may not be any way to tell, but I'd like to avoid this kind of stuff in the future. I have forged one knife out of this material before with no problems, but I started with a piece from the middle of the spring, and did not do any funky stuff with it prior to the initial forging.
 
Probably stress cracks already in the steel,one of the bad things about using car springs.Atleast you found them now,you could have spent a lot of time forging ,H/Ting and found them on cleanup.
Stan
 
Thanks, Stan. That's what I'm leaning toward, as they're only out on the tapered end of the spring. I forged out the other end of the same piece, and didn't see any cracking. I won't be using any of it for a blade any time soon, though.
 
Any time possible, buy from a supplier. It isn't worth the disappointments using salvaged, or unknown steel. For what you get as an end result, knife steel is cheap.
 
I've used quite a few leaf springs over the years and have never seen what you saw. I'd say the cracks developed from you using the piece of spring to warm up your quench oil.
 
I agree with Ray. I used to use a pieces of caterpillar leaf spring to pre-heat the anvil and power hammer dies before I had a heated shop. I also use a chunk to preheat my quench tank......after about a half dozen times, it was full of spider cracks.
 
Well there you go, a master smith and also the master of all things springy. I love the internet :) Thanks, fellas.
 
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