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- Jul 29, 2014
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- 2,737
I added a cheap bench grinder specifically for carbide work, and stuck a 3M Scotchbrite deburring wheel on the left hand side. It's OK, but overall quite out of balance to the extent that my tools vibrate off the bench when it's on.
Tired of that, I saw somewhere a balancing arbor for a surface grinder, with two unequally weighted washers placed back to back to create a net offset gm*cm arm. I started to make that, but it was going to need the rotary table (pretty heavy) and at heart I'm pretty lazy.
And, I wanted to get rid of the cheapo pressed steel washers that were OEM. Combining those concepts, i.e. good washers and unequal weighting, I made two washers and put a hole to lighten, producing a net moment. The two washers are identical, so if installed in opposition the net moment is zero, and if installed aligned, it's twice the moment of either.
So the idea is find the lightest part of the wheel, and I saw a lot of fairly complicated ways to do that, with levels, blade edges, etc. Reflecting back to the lazy part, I just put the grinding wheel to be balanced on an axle along with the two washers, then supported them on 123 blocks. This was completely sensitive enough to determind the light/heavy imbalance. and fancy leveling is not needed if you just rotate the blocks until the wheel doesn't roll off by itself.
Then, starting with the washers still in opposition, align them perpendicular to the lightest spot on the wheel. Now rotate them in opposite directions equally so that the heavier parts move toward the light position of the wheel. Eventually the wheel will be in balance, unless the washers can't add enough to achieve that. The first set I made I had to add another hole to each washer. That worked. The second set, for the deburring wheel, I just made a larger hole, and only one was necessary.
There's a video of the after effect of the balancing...wish I had done one before, but duh, It was really bad. But tools stay in place now.
Also, it's easy to clock the washers relative to each other and to any wheel, so swapping wheels does not involve starting over. However, these wheels have not been dressed so when my wheel dresser arrives, I expect it will take another balancing afterward.
Next step is to do this for the 8" grinder.
Tired of that, I saw somewhere a balancing arbor for a surface grinder, with two unequally weighted washers placed back to back to create a net offset gm*cm arm. I started to make that, but it was going to need the rotary table (pretty heavy) and at heart I'm pretty lazy.
And, I wanted to get rid of the cheapo pressed steel washers that were OEM. Combining those concepts, i.e. good washers and unequal weighting, I made two washers and put a hole to lighten, producing a net moment. The two washers are identical, so if installed in opposition the net moment is zero, and if installed aligned, it's twice the moment of either.
So the idea is find the lightest part of the wheel, and I saw a lot of fairly complicated ways to do that, with levels, blade edges, etc. Reflecting back to the lazy part, I just put the grinding wheel to be balanced on an axle along with the two washers, then supported them on 123 blocks. This was completely sensitive enough to determind the light/heavy imbalance. and fancy leveling is not needed if you just rotate the blocks until the wheel doesn't roll off by itself.
Then, starting with the washers still in opposition, align them perpendicular to the lightest spot on the wheel. Now rotate them in opposite directions equally so that the heavier parts move toward the light position of the wheel. Eventually the wheel will be in balance, unless the washers can't add enough to achieve that. The first set I made I had to add another hole to each washer. That worked. The second set, for the deburring wheel, I just made a larger hole, and only one was necessary.There's a video of the after effect of the balancing...wish I had done one before, but duh, It was really bad. But tools stay in place now.
Also, it's easy to clock the washers relative to each other and to any wheel, so swapping wheels does not involve starting over. However, these wheels have not been dressed so when my wheel dresser arrives, I expect it will take another balancing afterward.
Next step is to do this for the 8" grinder.
