rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jul 29, 2021 12:18:35 GMT -5
I need to evaluate about 25 used diamond grinding wheels our club received as a donation. All are name brands and the grit sizes are marked. Is there a standard why to check out a used wheel? I do not make cabs so I am at a loss as to how to check them out. I have an arbor I can quickly mount them to and spin them up. I would like to be able to say there is about x percent of life left on each wheel. The last person who used them died so there is no one to ask. I ran the first one on a glass plate and looked at the cutting pattern but that does not seem very safe. Thanks for any input.
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Post by mohs on Jul 29, 2021 12:36:49 GMT -5
Yo with a stone wheel the ring test was the method most used basically insert a rod ( screw driver or such) in the arbor, hold wheel up free hanging on the rod, and tap it gently around on the side ...mostly. Listen for a ringing sound. A dull thudding sound may indicate a hairline crack. A cracked wheel spun up on high rpm grinder may explode. Quite harmful! Eye shields always and a mask. Anyway on lapidary type wheels, at lower the lower rpm (1725 or less) speeds Its usually not as critical. Good visual inspection. Heck ring test it anyway. Its sort fun thing to do. Especially with a stone wheels. Always kept a crack one aside as an example. 25 wheels as a donation! Rolling. That the beginning expense of this rock’n hobby. so your off to grinding start as oppose to grinding stop
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rewdownunder
spending too much on rocks
Member since March 2012
Posts: 357
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Post by rewdownunder on Jul 29, 2021 13:35:58 GMT -5
Thanks for the input I hope some of these are good because wheels are the largest expense for our club shop. We removed all solid SC wheels several years ago because of safety I like them for smoothing agates but in a group setting just do know how well they are taken care of. I never run SC wheels at full rpm. Several of our members make blades and they love them for working steel.
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Post by Peruano on Jul 29, 2021 14:53:08 GMT -5
Evaluating diamond wheels is probably a subjective process but even worn wheels have a place in the polishing process. I'd pick a set of stones that I was familiar with and jump on to see how aggressively the coarser grits can start the doming process. For the finer grits again its a matter of your seeing the degree of progress you would expect from a known wheel. For example, a bit of time on a 280 should leave the stone significantly smoother to the touch, and properly used, a 600 or 1200 should produce some shine. Worn belts are valuable in certain applications. Worn wheels also have a place for stones that you feel might be a bit more fragile or susceptible to chippping.
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