Contact wheel bearings

Scottickes. What machine the hub to 1.124" on both sides and only go .312 deep and get 2 of the bearings mentioned by Rob with the c3 clearance deal. Then press a bearing into each side of the hub. Then make the shaft with 1/2 NC threads on the one end that threads into th tool arm then a shoulder the is wide enough to position the wheel the correct distance from the arm when the threaded side is tight against the arm and the shaft side is against the inside race of the inner bearing then the shaft is 1/2" or whatever the correct size is for the R8-2rs-c3 bearing. The smooth part of the shaft drop to 3/8 and be threaded NC at the outboard side of the outboard bearing, Then I could place on a thick washer like collar 3/8 id and slightly large OD than the inside race of the bearing. Then when the wheel and bearing assy if on the shaft I would slide on the collar and thread on a nylock nut. The bearings would be press fit and trapped between the shoulder and the collar. The wheel would be trapped between the 2 bearings outside race. Removing that amount of aluminum on the very inside of the wheel should not affect the balance. If I was not completely true with my machine work I would have to turn down the outside or the wheel to make it true. That would affect the balance, I would need to remove a corresponding amount of aluminum 180 degrees from where I removed surface material.

How are regular contact wheels mounted on bearings and what is the bearing number. My tracking wheel and 2" wheels on my platen attachment all use 2 bearings each marked R8RS with the exact dimensions of the bearing above. Their "shaft" is simply a 1/2 bolt. The head rides on one side and and the other side just has a nut up against the inboard bearing, then the remainder of the threads are threaded into their positioner piece. Simple and they must spin far faster than a 10 inch wheel.

Thanks again for everyones input.
 
If you're machining a shoulder inside the hub that the two bearings will seat against from either side, then the set up as described will work great. The bearings must be press fit into the hub. The shaft that goes through the bearing must "NOT" be press fit. No tighter than line to line. Even having .0005" smaller shaft than the bore of the bearing is acceptable. The rotating part of the bearing needs to be press fit. The stationary part of the bearing needs to be line to line fit or slightly loose. The clamp up that you described will keep it from spinning on the shaft and will keep it stationary.

Ball bearings are designed to run at high speeds, so you shouldn't have any problems with that.

It sounds like you have this all under control.

Ickie
 
Thank you. I will do it that way. Everyone helped to clarify what to do. I don't know why I didn't take one of the wheels off the parts I do have and look sooner. I did learn some stuff and that is the important thing. Especially the clearance part never knew that bearing were made to fit that way and you could get them for multiple clearances.

Scottickes, congrats on your purchase of the KMG. Nice buy with all variable speed and the attachments. Your going to be a very happy man. I love mine. Now to get some bearing in this wheel and mount it on mine and learn to do a hollow grind.
 
I use a spacer to support the inner races of the bearings. This lets you use a standard bolt which clamps the inner races to the spacer without binding the bearings. Here's a pic:

Mvc-851s.jpg
 
Got it thanks. Great idea and I will be adding a spacer like this to mine for sure. I appreciate all the help and advice. I will be having it going maybe next weekend if I can get the bearings on Saturday.
 
ib2v4u said:
Scottickes, congrats on your purchase of the KMG. Nice buy with all variable speed and the attachments. Your going to be a very happy man. I love mine. Now to get some bearing in this wheel and mount it on mine and learn to do a hollow grind.
Click to expand...

Thanks on the congrats! I've been hollow grinding for years on a 6" stone grinding wheel. It can only get easier, I would think!

Ickie
 
Your going to love your KMG. I love mine. Simple and uncomplicated design, very well built. Easy to work on and use. To me the mark of greatness in equipment. I really want to thank rfrink and his KMG company for a great piece of equipment. An additional thanks for jumping in an showing how it was done when I am not getting a piece from him. Don't know how it could be any better.
 
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