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Heat Treating and Metallurgy Discussion of heat treatment and metallurgy in knife making. |
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#1
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Brittle Edge
Just finished up an S30V kitchen blade - thin edged, hollow ground. Doesn't hold an edge real well.
The brass rod test kinda created a wire edge. But, no major chipping or anything, but the edge just doesn't hold up, like S30V should. It's about 61HRC. Maybe that's too hard? I'm thinking it not just a hardness issue. I'm thinking maybe I have to change the angle, but it's just under 20 degrees. That's not very steep. It's weird. I'm feeling lost here. Steve |
#2
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Steve: What was the HT cycle you used?
__________________ Stay Sharp, RJ Martin Knifemaker www.rjmartinknives.com |
#3
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Did you strop or buff off the burr before doing the brass rod test? If there's a burr that's aligned with the edge (like butchers like em) then it'll fold up on the brass rod test not giving accurate results on the "real" edge under the burr.
__________________ ~Andrew W. "NT Cough'n Monkey" Petkus |
#4
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I'm not at home with my book, but by memory
1200 for 2 hrs, oven cool for stress relief 1950 for 20 minutes Plate quench 8 HRS cryo 2 hrs 400 2 hr 400 -------------------------------------------- You know, RJ, it might be the angle. I usually use 15 degrees, but this is going to a family with little kids, and plenty of abuse. So, I went 20 degrees. Maybe I'm not used to this edge. I did some apple slicing. Then cut up some aluminum cans. The edge is still the same. No chipping or rolling. It just doesn't shave (well just a bit). It's not a great slicer, but it's not getting worse. Maybe I'm not used to this cutting angle. -------------------------------------------- AWP - Thanks! I used a leather belt, but that might not have removed the burr like I thought. It's gone now. Steve |
#5
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Steve: 400 is kind of low for S30V. I use 550 or 600, depending on the knife. My guess is the edge quality would improve if it were a bit softer.
__________________ Stay Sharp, RJ Martin Knifemaker www.rjmartinknives.com |
#6
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OK Boss, I'll do that on some blades from the same batch.
Thanks, Steve |
Tags |
blade, knife |
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