Well, I tried to reply to Stick and Nick, but it did not appear here in the thread. Making a wall cabinet with raised panel doors, and using a set of rail & style cutting bits with top bearings. Straight portions are not a problem as the fence on the router table allows for incremental stock removal until the last pass against the bearing for finish depth. The problem comes with using several passes to remove stock in the arch top rail (Cathedral style) using hand feed. Plan was to begin with a 1 1/4" O.D. top bearing and then step down to reduce the stock removal per pass. Next to last pass made with the original supplied bearing, but with several layers of tape on the bearing. Last pass - remove the tape and run rapidly to prevent burn marks. I checked the top shaft on the bit and it measures 0.3105" so the ASME size will fit (should). Went to my local bearing supply house, looking for metric mearings that might work. Quote was $ 90.00 per bearing. Found some on line, (under 10 bucks) but was concerned that switching between metric and English might create a problem. I guess I did not think through the problem quite enough, or I would have realized that the metric actually had the larger I.D. Just for my enlightenment, should I run into a problem with excess clearance, can one use motor bearing shims ( 0.0030, 0.0050, 0.010 and cut strips as fillers on the inside of a mismatched I.D. and still get good results ??