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Old 12-22-2003, 08:11 AM
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MaxTheKnife MaxTheKnife is offline
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Join Date: Jun 2002
Location: Paris, Arkansas
Posts: 581
It works just like Sweany said Bear. The cracks will show up as a thin, dark line on a spring that's heated up to a bright red and viewed in a dark place like under the forge. Think of it like this and it might help. The crack wants to cool faster than the solid steel so the edges of the crack, as small as they are, will get dark shortly after taking the spring out of the fire because of the faster cooling. You have to do this in a fairly dark place. That's me, a crack inspector. 5160 spring steel is all I've been using lately besides the odd file here and there. When you find a crack, do like Sweany says and just cut that section out of the spring. Mark it with a file or chalk marker before all the color goes out of the steel. Sometimes you get lucky and it's right in the middle of the spring going lengthwise. That's good because you can split the spring in half and have two slabs of steel to make knives from. I stopped buying knife steel a couple of years ago because I've had such good luck with leaf springs. Like Gib said, you need to avoid the 'sprung' leaf springs because cracks are usually what cause them to spring in the first place. Trying to weld the stress cracks back together sounds like an excercise in futility to me. Who knows how long the cracks have been there? And besides, 5160 just doesn't want to weld to itself in my experience. And believe me, I've tried many times. It must take a special flux or something. Or maybe a blacksmith's incantation at the right phase of the moon. Good luck with your leaf spring project and don't automatically assume that those old springs are going to be full of stress cracks. Do your homework and inspect for cracks as you use it. Some of that old steel is the closest we're likely to come to 'virgin' steel these days. There's alot of truth in that statement if you look at it close.

Last edited by MaxTheKnife; 12-22-2003 at 08:14 AM.
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