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Dustin Stephens

leaf springs

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Hello all, im sure its been asked a thousand times but im new so please bear with me. I have some leaf springs I want to turn into knives, what needs to be done to them to make them ready to forge and stuff? I plan on forging some and stock removal on some. What steel are leafs usually made from? Do I need to anneal them first and such? Thanks in advance

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Leaf springs are usually pretty good for knives and so forth. Annealing helps soften them up, but here is a problem. The older a spring, the more of a chance they have stress fractures in them, many so small they are hard to see. Working them for a bit at welding heat and folding them over a few times to make a billet can really help with this though.

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Leaf springs are often 5160, old ones (60's or earlier) may be 1095. There are some other steels they might be, but treating them like 5160 works ok. I would normalize them before grinding (heat to non-magnetic and let air cool).

 

The sort of problems you might run into are: cracks (old or used springs may have stress cracks), deep rust pits, and the biggie, you never know what steel you've got, so you're never sure how to heat treat it for best results without testing each piece.

 

I assume that you want to use leaf springs because you can get them for nothing, or nearly nothing. However, buying 5160 from Aldo is pretty cheap, and you know what you're getting. If there is a shop in your town that makes springs for cars and trucks, you should ask them about cut offs. They will know what the steel is, and 6 inches of 1.5 x .250 is enough for two forged blades, maybe three small ones.

 

Geoff

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Good info guys, thanks, my only reason to use them is yes they are free and i want to get proficient enough before i fork over some dough to get good steel.

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A suspension shop that adds new leafs to vehicles have cut offs you can get free - or scrap price. Cant beat that and they are usually in more manageable sizes this way and BRAND NEw so none of the issues Geoff warned you of. My first leaf spring i salvaged i flattened out and was filled with cracks :(

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I've used a bunch of these and used them to hone my skills and have had relativly good luck treating al the springs i get as if they were 5160 for heat treatment. Also to just stay on the safe side quench them in oil first then do a hardness test with a file if it hardens great if not try in water. I had a small knife blade i quenched in water and watched it shatter but then again i might have had it over heated as well sooooo... Safety first.

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Great info here already. Although I'm all for re-using stuff (I'm about to make a bunch of Christmas presents with tractor mower blades).....I recommend steering clear of unknown steels when first starting out. You won't learn much trying to heat treat it. Good, known steel is cheap. I'd argue steel is the cheapest part of knife making (unless you get into that crazy super steel BS) :P

 

Good luck friend!

Edited by Austin_Lyles

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Forge out a couple quick test blades (think butter knife/letter opener)

 

Don't invest too much time, but do clean 'em up reasonably.

 

Heat treat them (take note of your process), them test them...

 

Check the hardness, bend 'em, break 'em, etc.

 

Adjust your process until you're happy, then make blades.

 

And to repeat the above replies: it you have cracks, you'll have cracks.

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