Which way round to mount a FK12 bearing ?

[routercnc]

I've used BK bearings (similar to FK but in block format) both ways around depending upon package space with other parts of the machine. Didn't notice and problems from doing this.

I assumed that angular contact bearings could take equal loads in each axial direction therefore it didn't matter. But thinking about it I guess one face of the flange/block could be more accurately machined 90 degrees to the main axis? But don't know for sure.

If both faces are 90 degrees to the main axis then I can't see a reason for not connecting it the other way around if you need to.

You could also build it the 'wrong way round' then use the CNC machine to make new bits including the clearance hole to mount it the 'right way'.

[EddyCurrent]

But thinking about it I guess one face of the flange/block could be more accurately machined 90 degrees to the main axis?

Thanks, yes that's what I thought later, anyway I likely wasn't trying hard enough before because I've done it now and quite easy.

Drill largest feasible hole in bracket, in my case about 19mm using a cone cutter (it's hard work and hardly cuts), position bearing block on bracket and clamp, drill mounting holes in bracket using bearing block as a guide, bolt bearing block to bracket with some spacers between, mount in lathe chuck, use boring bar to open hole out to final size.



I think the answer to my original question is this;
The bearings can be used either way around but the face next to the boss is the one that goes up to a bracket. This allows for the fact that the mounting holes are counter bored on the flange face and it's possible that the face next to the boss is more accurately machined.