06-25-2018, 04:33 PM
In order to gain understanding of the meat processing plant's sharpening system, and see what I could determine about deburring and honing on high speed buffers, I tried to replicate their procedure to see what it might take to heat the edge enough to soften it.
I started with a vintage Gerber Balance Plus boning knife, which is a little harder than regular German kitchen knives, and probably very close to the best knife steel used in the meat processing industry. I re-profiled the bevel to about 10 dps with a 120 grit belt, then refined the edge with a used 400 grit belt. I viewed the entire edge at 60x, and everything looked great, including the rather large burr sitting straight up off the edge.
I don't have hard felt wheels because I haven't heard of any other use besides sharpening, and I don't use buffers in my sharpening process for two reasons. First, it's too much refinement. Second is lack of clear angle control on a wheel, which has previously resulted in spotty results.
Don't get me wrong though, I have four 3/4 hp industrial buffers, and I use all 8 wheels on every knife, so I have plenty of experience on the machines. I have never needed to use water (dip bucket) to cool anything while buffing. The amount of pressure I use is only enough to get the job done without causing much heat. This has always worked plenty well enough for me, no matter what I'm buffing.
I use a hard sisal wheel with black compound regularly, so I gave that a whirl. I did not change anything about the way I normally use this wheel. In other words, I didn't apply any more or any less pressure than normal, and I didn't use more or less compound than normal. Everything was just standard routine.
It took me way more than 30 seconds to remove the burr. I'd make several passes then examine at 60x. Each time I looked, I was satisfied with the steady progress, but I was surprised with the tenacity of the burr. On the other hand, I wasn't developing much heat at all, so I did raise the pressure a bit, and that made a difference.
After two more series of passes the edge was remarkably clean, and the blade was notably warm to the touch, which I would estimate to be around 85°-90°F. The entire process had taken 4-5 minutes, more than half of which was spent inspecting the edge.
Please remember, this is something I totally dismissed many years ago. I did not expect the edge to be very sharp, so I was pretty surprised that it measured an amazingly consistent BESS 65-70! Maybe I've been overlooking something...
I wasn't through of course. I needed to finish the edge with white compound. My white compound wheel is a well manicured sewn cotton buff, so I figured I'd give it a shot rather than loading white compound on my sisal.
Trying to keep it real, I applied more pressure as I made 10 passes per side, thinking this would be closer to what the meat plant's sharpener might do. I didn't fool around at all, and this probably did take about 30 seconds. The blade got warmer from this single series of passes than from the sisal wheel, but was not close to uncomfortably warm. I was a little surprised, but a sewn cotton wheel probably can't equal the friction of a felt wheel.
I was pretty sure I had rounded the edge by now, but it sure was nice and shiny! Actually, the edge was popping arm hair very aggressively. I took it in for a measurement, and I'll be darned if it didn't now measure BESS 55! Holy cow. This was unexpected, but the 3 finger test revealed something else. The edge was fairly slick.
I couldn't just stop there. I took it back to the white wheel for another shot. I had a pretty good idea of heat generation, so I just wanted to see if I could get a little sharper.
That's why you should always quit while you're ahead.
I started with a vintage Gerber Balance Plus boning knife, which is a little harder than regular German kitchen knives, and probably very close to the best knife steel used in the meat processing industry. I re-profiled the bevel to about 10 dps with a 120 grit belt, then refined the edge with a used 400 grit belt. I viewed the entire edge at 60x, and everything looked great, including the rather large burr sitting straight up off the edge.
I don't have hard felt wheels because I haven't heard of any other use besides sharpening, and I don't use buffers in my sharpening process for two reasons. First, it's too much refinement. Second is lack of clear angle control on a wheel, which has previously resulted in spotty results.
Don't get me wrong though, I have four 3/4 hp industrial buffers, and I use all 8 wheels on every knife, so I have plenty of experience on the machines. I have never needed to use water (dip bucket) to cool anything while buffing. The amount of pressure I use is only enough to get the job done without causing much heat. This has always worked plenty well enough for me, no matter what I'm buffing.
I use a hard sisal wheel with black compound regularly, so I gave that a whirl. I did not change anything about the way I normally use this wheel. In other words, I didn't apply any more or any less pressure than normal, and I didn't use more or less compound than normal. Everything was just standard routine.
It took me way more than 30 seconds to remove the burr. I'd make several passes then examine at 60x. Each time I looked, I was satisfied with the steady progress, but I was surprised with the tenacity of the burr. On the other hand, I wasn't developing much heat at all, so I did raise the pressure a bit, and that made a difference.
After two more series of passes the edge was remarkably clean, and the blade was notably warm to the touch, which I would estimate to be around 85°-90°F. The entire process had taken 4-5 minutes, more than half of which was spent inspecting the edge.
Please remember, this is something I totally dismissed many years ago. I did not expect the edge to be very sharp, so I was pretty surprised that it measured an amazingly consistent BESS 65-70! Maybe I've been overlooking something...
I wasn't through of course. I needed to finish the edge with white compound. My white compound wheel is a well manicured sewn cotton buff, so I figured I'd give it a shot rather than loading white compound on my sisal.
Trying to keep it real, I applied more pressure as I made 10 passes per side, thinking this would be closer to what the meat plant's sharpener might do. I didn't fool around at all, and this probably did take about 30 seconds. The blade got warmer from this single series of passes than from the sisal wheel, but was not close to uncomfortably warm. I was a little surprised, but a sewn cotton wheel probably can't equal the friction of a felt wheel.
I was pretty sure I had rounded the edge by now, but it sure was nice and shiny! Actually, the edge was popping arm hair very aggressively. I took it in for a measurement, and I'll be darned if it didn't now measure BESS 55! Holy cow. This was unexpected, but the 3 finger test revealed something else. The edge was fairly slick.
I couldn't just stop there. I took it back to the white wheel for another shot. I had a pretty good idea of heat generation, so I just wanted to see if I could get a little sharper.
That's why you should always quit while you're ahead.