Home made grinder wheel shim question

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v8r

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Mar 6, 2009
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I'm building a 2x72 grinder, and have a question. What is everyone using for shims between wheels and metal surfaces. I have purchased Machine bushings at the local hardware store. When I go to snug the bolts down that are holding the wheels, the wheels have a lot of drag.
I would like to find some shims that have a smaller Outside Diameter (same as OD of inner bearing race of wheel), but with a half inch inner diameter. Any ideas?
 
I was able to find smaller machine washers at my local hardware that were smaller OD and same clearance ID for the bolts.

Jay
 
I used some 14 gauge (I think? They're about .073 to .075 thick) machine bushings from the local hardware. You can get them from McMaster Carr in packs of 25, 1/2" ID, 7/8" OD.

That said, these won't make any difference with binding if you don't have interior spacers to keep the bearings from binding on the inner bore of the wheel.
McMaster also sells unthreaded spacers in various lenghts and materials. You can probably find one that will work for your wheels if they don't already have them. What kind of wheels are you using?
 
Search for "bearing shim" at McMaster. The shim should only make contact with the inner race of the bearing, unlike washers you find from the hardware store.
 
V8R, I am just guessing but I think the hardware store may have given you washers and not genuine machine bushings. USA knifemakers sells them 10 at a time but a nut and bolt store in the industrial part of your town will probably have real machine bushings for not so much money. Also, I agree with Andrew about needing a spacer tube between the bearings in your wheel. The only way to find out is push out the bearings and spacer and then reassemble. Have you measured your "bushings" for outside diameter and compared that to your bearing inner race? You could check the specs on machine bushings on the Mc Master Carr website and compare to your bushings before doing any thing else. Are your wheels 1/2 inch bore? It should be easy to fix this problem. I hope this helps. Larry
 
v8r
I built my own 2x72 had the same problem tried shims /washers ect still could not get them just right , also checked the straightness of the 2 wheel bracket , everything looked good , but I had burned up a couple of bearings in my wheel set and had wear on one of my wheels. I finally bought the bracket from oregon bladesmith and the 1/2 holes that go through the bracket are thread then has a lock nut on it solved the problem with the threaded hole you can tighten the bolt to a specific tension then set the lock nut . bought my wheel set from him also.
 
I drilled the threads out of the appropriate bolt sizes for spacers on mine, been running it for about 2 years never had a problem
 
Thanks for the replies everyone. I purchased the wheel set from Oregon blade maker about a month ago.
I am just about finished with the mockup of the grinder. I had actually thought about ordering shims from Mcnaster Carr already, and will do that. It looks as if they have some with a smaller OD, but it is still slightly larger than the OD of the inner bearing race. If this doesn't work I will put some helicoils in the wheel mount plate and try tightening the axles in to the plate with a lock but.
 
v8r said:
Thanks for the replies everyone. I purchased the wheel set from Oregon blade maker about a month ago.
I am just about finished with the mockup of the grinder. I had actually thought about ordering shims from Mcnaster Carr already, and will do that. It looks as if they have some with a smaller OD, but it is still slightly larger than the OD of the inner bearing race. If this doesn't work I will put some helicoils in the wheel mount plate and try tightening the axles in to the plate with a lock but.
Click to expand...

Look up this part number at McMaster: 97669A290
They appear to be the same size I get at the local big box store.
 
I use the machine bushings on my homemade 2x72. Basically looks like a washer with 1/2" i.d. Use a self locking nut and don't tighten it so tight. I have great success this way and I operate at 7250 sfpm. If you over tighten and get too much drag the bearing will fail sooner than it should. Needs to be snug so the wheel is steady on the bolt but loose enough for the wheel to spin. Link to my sander. http://imgur.com/a/e3VdB
 
Using a nylock nut or some thread locker is a good idea.
 
I currently have lock nuts on it. I think the problem I'm having is more the drag from the department store machine bushings rubbing the seals on the bearings. It would also be nice if there were internal spacers on the wheels, so that it wouldn't matter how tight you tighten the bolts, but this isn't reality unfortunately.
 
Copper plumbing pipe makes easy spacers of any length you might want to make. It would indeed be difficult to get it setup with nothing for the inner race to press against when you tighten it. My previous comment was based on my solid aluminum wheel which has a machined pocket for the bearings that acts as a spacer for the inner race.
 
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I ended up making axles for the wheels. I tightened them down on the plate. Think skateboard truck axle. Then I used a Nylock nut on the end of the axle. It's adjustable, and no more drag.
 
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