beckerkumm
Hot Rolled
- Joined
- Aug 5, 2014
- Location
- Wisconsin Rapids WI
The smaller bearing can be a sealed due to the higher rpm limit but generally running C3 bearings in a spindle is a cost cutting measure to avoid either an oil distribution system or expensive bearings. A stamped steel cage bearing will seldom be higher precision than ABEC 3 because the cage becomes the limiting factor. The proper top bearing if you can find one is a phenolic or brass cage ABEC 5 or 7 with normal or C2 clearance. Since a large shaper seldom runs over 6000-7000 rpm an ABEC 3 SKF Explorer type bearing in C3 is cheaper unless you find a deal on ebay for the precision one. When running a C3 in a shaper, I'd run the spindle a few minutes before cutting anything to tighten up the runout. I think you will find that warming up the bearings by running them will reduce the runout as the clearance is reduced by the temperature increase. Not ideal but that is why newer shapers cost less than the old ones with large high load bearings in an oil drip system. Dave