KMG Grinder bearings question

[melsdad]

A question for those that have a kmg grinder or a home built clone. What size bearings are pressed into your idler wheels, and contact wheels? I know the I.D. is .500" I believe the O.D. is 1.125", and the width is .313" If this is correct can you tell me what if any visible markings are on the bearings.

[Drq]

I just grabbed some off the shelf at work a while ago that the boss said where gather dust, if you want I'll take a look at the number, but you really should just be able to go to a bearing shop and tell them what you need. Either that or if your up to it Ebay is a good place to find cheap bearings.

[BIGGUNDOCTOR]

Don't assume that they are in inches, as most of the bearings I have dealt with lately have been metric sizes. .313" could be 5/16"-.3125, or it could be 8mm -.315". Make sure that you use some good calipers, or a micrometer to measure them, as a lot of standard metric, and inch measurements are very close.

The best bet is to pull them, and run them down to your local bearing house. You may be able to find cheaper bearings at some discounter, but the industrial houses will usually have better quality bearings. Timken, FAG, SKF, NTN, were the brands that we mostly used at Jelly Belly. None of those were marked China. USA, France, Italy, Spain,Japan, but not China.

Bearings come in different classes of fit, the higher the number the tighter the fit of the races to the balls, or rollers. Some milling machines have class 7 bearings in their quills, while an electric motor may only have a class 4. The higher the class the more $$$.