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High-Performance Blades Sharing ideas for getting the most out of our steel. |
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#1
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Grinding- Hard vs Soft?
Question: If you heat treat your blade before grinding the bevels, does it cause more stress in the blade steel?
I have always normalized my blades after rough grinding in order to relieve some of the stress caused by the grinding and done only the finish grinding after H/T but I know some of you do 100% of the bevel grinding after H/T. I have some blade steel that I have had surface ground to .065" to make fillet knives from and am concidering heat treating before grinding the bevels but would like some opinions before I do. Gary |
#2
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As long as you keep the blade below the temper temperature, there should be no problem grinding post heat treat. Many folder makers do so. Actually, I think Rob Simonich has his S30V midtech line of fixed blades ground after heat treat. You need to watch the heat though, especially on those thin blades. Without much mass to distribute the heat generated, they can get very hot, VERY fast. I'd suggest using a very coarse belt to remove most of your material so that you generate less heat, and be very careful around 400 grit.
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#3
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Jerry,
Are the potential stresses caused only by the heat generated by the grinding or are there other causes of stress in the steel. Gary |
#4
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Uneveness is a cause of stresses (seen as warping); it's not just the heat from grinding. Also, anything that creates a stress riser (cracks, filework, etc.) will be amplified during HT.
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#5
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post HT grinding
Hi everyone,
I'm still new to all this, but I've had all sorts of advise. I suppose technically, if you don't ruin the temper, that should be OK. I had enormous trouble making kitchen knives from thin stock. I use O-1 precision ground for just about everything. The 75% ground blades (3/32inch stock) would warp like crazy when heat treated which I do myself. The troubles went away when I ground only the most rough initial bevel into the edge before heat treat. I'd do my usual quench and temper cycle, then grind the bevels in hard. I found that on small, thin knives, grinding hard wasn't too bad. Mind you this was on O-1 and 1095. I cringe at the thought of having to do 90% grinding on S30V while hard ! I did this with one of my D-2 (61HRC) hunters and it was near impossible to grind. It worked out OK but it was frustrating. I also find that when grinding hardened steel, a given grit size belt produces a finer finish compared to when grinding annealed with the same belt. In that sense it is actually quite nice to grind hard but I use up more belts. This then catches up with me because the overheating problem becomes accelerated with the belt that starts to go dull. have other people met this same phenomena ? Is it a simple matter of physics (simply more difficult to grind, so finer scratch pattern) ? Thanks for your help. Cheers. __________________ JASON CUTTER BLADEART Jason Cutter @ Dr Kwong Yeang Knifemaker, Australia (Matthew 10.16) |
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blade, knife, knives |
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