BK12 end float?

[birchy]

I agree. It doesn't seem right that we have to misalign the bearing to prevent end float. Are these just crappy bearings or am I being thick?

[irving2008]

I agree. It doesn't seem right that we have to misalign the bearing to prevent end float. Are these just crappy bearings or am I being thick?

Is the bearing seat machined square? and spotlessly clean.. no swarf or dirt in there?

[birchy]

Haven't checked squareness of the bore/seat. Will check that tonight. Seats should be pretty clean as I stripped the blocks, cleaned them and greased the bearings.

Could I be OVER tightening the nut? I'm basically putting a piece of copper tube over the ballscrew shaft end, holding with a pair of pliers and tightening the nut until the pliers slip. Could this have damaged the bearings??

[birchy]

Problem solved. Couldn't get any preload with the bearings back to back so fitted a 0.2mm shim washer between the bearings to separate the outer races. I was then able to preload the bearings which worked out at finger tight plus about 1/4 of a turn of the lock nut. End float is now less than 0.01mm. Every day day is school day!

[Gytis]

glad to hear that you sorted it out !