JHCC Posted November 1, 2017 Share Posted November 1, 2017 I'm a long ways off from being able to afford a 2x72 grinder, so my dabbling forays into knifemaking have relied heavily on my 4½" angle grinder. It just occurred to me that since that grinder has a universal motor, I should be able to plug it into my variable transformer (currently controlling the speed on my forge blower) and run it at a lower speed. Grinding would take longer, but would be cooler with less risk of ruining the temper. Anyone have any thoughts? Is there any reason (electronic or otherwise) that this would be a really bad idea? Quote Link to comment Share on other sites More sharing options...
Jim Coke Posted November 1, 2017 Share Posted November 1, 2017 Greetings JHCC, You can purchase a variable speed 4 1/2 grinder. Milwaukee and Bosh make great ones . I ridged mount mine so thy can be clamped in a vise . Kawasaki also makes one but a cheaper model.. I have all of the above and for sure go to tools.. Forge on and make beautiful things Jim Quote Link to comment Share on other sites More sharing options...
Kozzy Posted November 1, 2017 Share Posted November 1, 2017 If I used a variac, I'd only do it on one of the sale-priced harbor freight grinders. You are going to be generating a lot more motor heat if you slow that down and you don't want to kill a good grinder. As to those cheap HF grinders...they sound like the gearbox is full of rocks but once in a while they just won't die. I've been trying to kill one my Dad gave me for years and the darned thing just keeps going no matter how badly I abuse it. I much prefer using my good grinders but it's nice to have a knock-around to drag through the mud without worrying. Quote Link to comment Share on other sites More sharing options...
JHCC Posted November 2, 2017 Author Share Posted November 2, 2017 2 hours ago, Kozzy said: If I used a variac, I'd only do it on one of the sale-priced harbor freight grinders. You are going to be generating a lot more motor heat if you slow that down and you don't want to kill a good grinder. Good info; thanks. 2 hours ago, Kozzy said: As to those cheap HF grinders...they sound like the gearbox is full of rocks but once in a while they just won't die. I've been trying to kill one my Dad gave me for years and the darned thing just keeps going no matter how badly I abuse it. I much prefer using my good grinders but it's nice to have a knock-around to drag through the mud without worrying. My grinder actually is one of those HF cheapies. Funny how it keeps suffering catastrophic failure right before the extended warranty runs out.... Quote Link to comment Share on other sites More sharing options...
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