Originally Posted by anoel  I used them for all of the axis on my cnc router...
I would not recommend unsupported bearings on any axis greater than 12" And really a Z axis is ok because the load is usually static or within an very restricted amount of movenment.
So for the Z I give them a thumbs up... X&Y greater than 12" a big thumbs down unless you went with grossly large rails... |
Dear Nathan,
I was only thinking about using 20mm dia. shafts and linear bearings for the Z axis. The shafts might be about 15 inches long between their top and bottom mounting plates. The sliding carriage that would take the spindle might be about 8-10 inches tall , and the linear bearings themselves would, to a certain extent, reduce the tendency of the shafts to bend. I have not done the deflection calculations yet, but my guess is that the two shafts would not deflect by very much. I will check.
Best wishes
Martin