Well my first knife is finished and it holds up well to chopping and slicing except for the last half inch of tip. Steel is 1084, thanks again Gene Martin, heat treated with an A/O torch till non-magnetic then quickly quenched in brine. Double tempered it at 380 for an hour each time. No grinding was done to the blade after HT but I did use a buffer to knock off the scale. It never got hot enough in the buffing to mess up anything so I think the problem was in the torch heating. I'll just cut the section out that won't hold an edge and make it a more agressive drop point but would appreciate advice on how to keep the tip from over heating to avoid the problem on the next one.
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Too much heat?
- Thread starter Martin S.
- Start date
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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Several things here.
First - "No grinding after HT" ????? If you didn't grind after HT ,I assume you did it all prior to HT, which means the edges were far too thin. Also there will be a "rind" of decarb and scale covering the surface. Go back and grind/sand the blade to expose the hard (and good) steel below the surface. Many first knives don't seem to cut right until they have been sharpened several times because of this (finally exposing a hard edge).
Second - It is hard to get an entire blade evenly heated with a torch. The tip could have been overheated and have extra decarb, or under heated and not properly hardened.
Third - While 1084 will survive a brine quench, it is severe. You might want to switch to oil while learning. The cutting problems have nothing to do with the brine, but in later blades you may encounter the dreaded "PING".
Stacy
First - "No grinding after HT" ????? If you didn't grind after HT ,I assume you did it all prior to HT, which means the edges were far too thin. Also there will be a "rind" of decarb and scale covering the surface. Go back and grind/sand the blade to expose the hard (and good) steel below the surface. Many first knives don't seem to cut right until they have been sharpened several times because of this (finally exposing a hard edge).
Second - It is hard to get an entire blade evenly heated with a torch. The tip could have been overheated and have extra decarb, or under heated and not properly hardened.
Third - While 1084 will survive a brine quench, it is severe. You might want to switch to oil while learning. The cutting problems have nothing to do with the brine, but in later blades you may encounter the dreaded "PING".
Stacy