Commando gearbox bearing C number

Would like to know the C number for internal bearing clearance for inside cover mainshaft bearing. A new one from a main supplier online sent one. it was a .001" interference fit in the aluminum casting. Heated casting, dropped in bearing. After cooled it felt notchy. I believe too little internal clearance.

Hey Doug, I believe they are all C3. WTBS, It shouldn't feel notchy.

I have struck this problem before, some bearing manufacturers have a thin outer cage therefor shrinkage occurs, look for a different manufacturer.

My new bearing is stamped KSM RL55 Japan lot 230831. I don't get any hits on google

the oem bearing is a deep groove, C3. Usually very expensive. 04-0099 or RLS5. Some are on EBay. I've had good luck with Japanese made bearings

That's RLS5 Doug, not RLSS

SKF's can be found at good prices

acadian said:

SKF's can be found at good prices

SKF RLS5 Deep Groove Ball Bearing, OPEN TYPE, No seals 5/8" x 1.9/16" x 7/16" | eBay

Find many great new & used options and get the best deals for SKF RLS5 Deep Groove Ball Bearing, OPEN TYPE, No seals 5/8" x 1.9/16" x 7/16" at the best online prices at eBay! Free shipping for many products!

www.ebay.ca

Click to expand...

ISO clearance class 'N' will not work for the intended application.


- Knut

I think my new bearing is CN. No C markings on it. I read that means CN. I see above recommendation for proper fit to be C3. Anyone wanting to know my supplier name can msg me

Not sure why some seem to think the clearance is C3, the drawing does not stipulate any old Dot code or clearance and has not done so since 1971. We sell hundreds of the RLS5 each year that owners fit without issue. Strange why someone is so quick to blame the clearance in this case when hundreds of others have no issues, it could be a case of the outer race not ground to finished dimension, yes, even the Japanese can miss one. Even using bearing fit can close down a bearing.

This is a chart of the internal clearances C2 to C5 by internal diameter of bearing.


For this size of bearing CN is between 3 to 18 microns and C3 is 11 to 25 microns radial clearance.

Note the overlap so you could get a CN bearing that meets C3 and also a C3 that meets CN.

Also note we are talking microns difference of radial clearance, compare that with other much wider tolerances on related parts and its doubtful a C3 would have any adverse effect.

Its quite possible the offending bearing is right at the bottom of the CN tolerance and a CN from another source will fix the issue but also that a C3 will also work.

Also note that the interference fit of the housing and the shaft decreases the effective internal clearance down from its free running state.

if you need the best in bearings, Boco Bearings in florida is the place to go.