Mounting configurations for open bearings? (rotated 90 degrees, upside down, etc)

[pswayze]

I'm hitting the drawing board on my first CNC machine and am planning to use the open linear bearings from Chai over at linearmotionbearings2008. What isn't explicitly clear in any of the auctions is how the rails must be mounted. Ideally, you would want to mount them so the opening on the open bearings faces down. But what if you rotate it 90 degrees along the axis of the rail? Or what if you hang it completely upside down? Is there a safety factor you would apply to the basic load rating?

[ger21]

I looked in a Thomson catalog, and it depends on the location of the bearing races. It would appear that under most cases, at 90° you'd have the same (or close to) 100% capacity. However, when upside down, capacity can vary from 45-75% of the rated load.

[pswayze]

Originally Posted by ger21 I looked in a Thomson catalog, and it depends on the location of the bearing races. It would appear that under most cases, at 90° you'd have the same (or close to) 100% capacity. However, when upside down, capacity can vary from 45-75% of the rated load.

Very interesting. This is good news for me because I was considering the 90° rotation. Thanks for the info.