Alan Longmire Posted November 7, 2021 Share Posted November 7, 2021 Graphic content below, so go away now if you're squeamish. No blood, that came about ten minutes later... So we all know that a belt grinder is capable of removing body parts (I didn't lose anything but skin and dignity) faster and even more easily than they remove steel. This means we usually treat them with the respect they deserve. A 36 grit belt at high speed will lay your knuckle open to the bone with a single slight touch. A 400 grit J-flex can slice you open like a bandsaw if you touch the edge of a slack belt at speed. Up until today, I'd never been mauled by a micron grit Gator belt, they've always been fairly innocuous. There were two causes to this incident, and a valuable lesson as well. The setup: I was running a Trizact A45 Gator belt at the slow setting on my KMG, about 700 surface feet per minute, or 900 rpm on a 4" drive wheel, doing the next-to-last finish grind on a tiny folder blade in my folder blade jig. Issue #1: Using the jig means using the work rest, which I don't usually use when grinding blades shorter than swords. The jig's baseplate is paper micarta slicked with Renaissance Wax. The work rest is also polished and slicked with the wax, to keep it from rusting and to keep things moving freely when it's in use. This also means that it needs to be cleared of swarf regularly when using the jig so it doesn't chew up the baseplate. I use a paintbrush for this. Issue #2: I allowed my mind to wander from the task at hand just enough to try and grab the jig when it tried to fly off into the water bucket. I know not to do this. If the grinder grabs something, let it go and jump away. I got complacent with the slow speed and the very fine belt. Result: The side of my right pinky finger touched the moving belt, which grabbed it and slammed the side of my hand into the work rest very damned hard indeed. Here is the result while it was still numb, less than 45 seconds after impact (I try to use these as teachable moments...) Not too bad, right? The thing about grinder burns is they are slow to bleed, and the thing about impacts is they numb the injury for a few minutes. I was nearly finished with the grind, so I kept working. Five minutes later, blood was dripping off the end of my finger, and blood will rust your stuff. So I called it a day and headed inside to clean it up. One hour later, a bruise is appearing down the entire length of the finger where it hit the work rest, and boy, is it not numb anymore! Lesson learned: ALWAYS keep the belt in mind, no matter what kind of belt it is. And don't try to catch something if it's falling off the work rest. Corollaries to lesson: A: If the work rest hadn't been there I'd have gotten away with a tiny nip. B: If I had not, as you always should when using them, had the work rest tight up against the belt, it could have easily broken the finger or even flayed it down to the bone before it bogged down the motor. Class dismissed, and don't learn this the hard way! 6 Link to comment Share on other sites More sharing options...
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