Thread: Making grinding wheel bushings; is this a dumb idea?

Picked up a nice 0.5 HP single phase Craftsman motor for $10 at the surplus tool place, plus a very coarse grinding wheel for 50 cents. For some evil reason, grinding wheels have 1" holes, while shaft diameters are anywhere from 0.5" to 1". Mine is 5/8.

I don't happen to have a bushing of the right size, plus I read all kinds of complaints about Norton's plastic bushings having too much slop, so I had an idea.

I cut 3 locating pins from 3/16" brass. I coated them with grease, and also greased a piece of 5/8" stock. Then I placed the stock in the center of the grinding wheel hole, and shoved the locating pins in place to insure that the stock is in the center of the hole. Then I started pumping in the hot glue.

When the gap was filled, I waited a couple minutes, then pulled the locating pins out & filled the holes left behind with more hot glue. When it all hardened, I pushed out my newly cast plastic bushing; a very ugly but perfectly fit plastic cylinder.

Now I'm afraid to actually try it.

Is there any online source of quality reducing bushings? I couldn't find one. Or should I try this again with some other material, like RTV perhaps?

I'm looking into a little phase angle controller that's rated for inductive loads to use as a speed control. Not as good as a variable frequency drive, but maybe good enough. Or maybe I'll gear it down as far as I can using pulleys.

If it was me i would probably try using a solid material like slow curing epoxy
Or try building it into a lathe first to make any bushings you need

I use pulleys for speed control. The largest is 10". The motor has a 3". The drive wheel size on the grinder can also be varied. Standard is 4" but 2" reduces the SFPM by 1/2.

That could work but I would use some casting material like JB putty, Epoxy, or similar. Duh..Grinding wheel sellers have reducing bushings all ready made up at a low cost. Or, call a buddy and have him make you a bushing.
Respectfully
~Richard

what cost are the cheap bushings?
Cheap enough to glue to the wheel so sloppy fit dont matter?

They fit tightly inside the bore of the wheel and should be about a couple bucks apiece. The wheel washers are what actually should transfer torque to the grinding wheel. The bushing just makes the wheel run concentric to the shaft. If there is slippage then there would be heat and that could make a hot melt soften and throw a wheel out of concentricity to the shaft.
Respectfully
~Richard

Please be careful as a grinding wheel can put out a whole lot of projectiles if it lets go while in use.

Also a good grinding wheel will have a 'ring' sound (kind of like a bell) when it unmounted and is very lightly struck. (Suspending it on a wooden dowel or pencil is a way to hold it for checking if it is not too large of a wheel) A wheel with a crack in it has a kind of muffled thud sound and not a ring.

Good luck and remember to wear your eye protection and not to stand in the projectile path if it decides to explode when you first fire it up.

Personally, I wouldnt trust anything that wasnt solid, like a proper bushing made of metal, or atleast high impact nylon or plastic. You could probably find a piece of 3/8 inch wall 5/8 ID pipe or atleast close enough that you could ream the inner or carefully grind the outer diameter. I have made a few to put a buffer wheel on my bench grinder, but I did use a lathe.

Here is a link that has something that would work:Order ARBOR SHIM in Small Quantities at OnlineMetals.com, you would have to stack some, though as they are only .125 inch thick, but they are already .625 center and 1.0 outer dia.

Or this machineable polycarbonate which is 1 inch outer dia, you just need to drill a 5/8 inch center hole:Order Plastic Polycarbonate Round in Small Quantities at OnlineMetals.com, but you would have to buy a foot.

There are probably more options on that website. Good luck.

McMaster-Carr has a bushing set for a couple bucks as it turns out