[ged]

which is the best choice for bearings in a home built spindle running @0-20,000 rpm? angular contact or ceramic or???Will be cutting aluminum,wood,plastics etc.1\2" endmill max capacity. thanks in advance.

[rustamd]

you will probably get much better responses in correct forum

http://www.cnczone.com/forums/showthread.php?t=38276

[NC Cams]

A/C's are available in both steel balled and ceramic balled variants.

The all steel bearings that are adequate for the lower speed ranges tend to be inadequate at the high limit speeds due to the additive centrifugal forces.

On the other hand, ceramic balled bearings are not as tolerant of abuse as steel balled bearings - thus they are poorly suited for "grunt, bury the tool work".

Although you may think you want 0 to 20,000rpm capability, chances are, you're going to be biasing your work one way or another.

Pick your bearing based upon your 80% useage potential, not "vaporware, it would be nice to have that capability" specifications.

[Big Daddy]

I think if I were building a 20,000 rpm spindle my concerns would probably be surrounding more of what (grade) of bearings vs. what type! For instance grade or class 7’s vs. grade or class 9’s! 9’s I think would give you everything you need with much higher precision that can handle the 20,000 rpm. I don’t think I’d go to ceramic simply because they can’t take any lateral loads. You never know when an accident could happen and take them out. For that reason alone it's a stupid idea.

[RICHARD ZASTROW]

ged, What's the spindle for? Mill, router or? Like NC mentioned, what rpm area is the majority of use? How much side load (radial)? Very high speed & light load are fine with ceramic balls but they are pricey and class 9's are super pricey.

The higher the class, the tighter the bearing tolerances and clearances. That also requires tighter tolerances for mounting them as well. If you don't meet the mounting tolerances, you will have a lot of $moked part$.

You might want to search some past threads for spindle bearings. This has been beaten a few times before. Good Luck!!