Re: Spindle bearing upgrade question
It is unlikely that you have taper roller bearings in a 2J2 style spindle. Every one I have seen has angular contact bearings as original equipment. The original veri-speed is limited to about 4200 RPM due to the mechanics of the system. I'm not sure how much speed the front pulley will take before risk of it coming apart at high RPM. I put a direct drive in mine and can turn 6000 RPM, 1.3:1 ratio, but I rarely turn it that fast, normally around 3200 max. I find this is fine even with carbide endmills, I just cut the feed speed back to match the RPM to keep a proper chip load.
If I really need high speed for tiny endmills, I have an air spindle that fits my main spindle and it will turn 50,000 RPM or so.
Jim Dawson
Sandy, Oregon, USA