Originally Posted by htrantx  Sam & Dick Z, thanks, and too bad that they are >20 Deg
I have found pre-loaded DAC bearings specifically designed for spindles and ball screws at:
http://www.ukf.de/english/index.html?&vonhier=0
The bearings also look like were designed for wearing on the neck with a thick gold chains... or at least the prices are (ABEC7 and up).
In the spindle section of their site, they have an example of a spindle design with 4 single row AC bearings arranged as \\ // and pre-loaded from two ends. Even with ABEC7s I would think two out of 4 bearings might be out of the pre-loading at a time. The alphas might be like |\/|,\|/|,|\|/,\||/, or perhaps I didn't understand the real pre-loading in this design.
Was this an example of 4 should be better than 2 design?
ht |
Precision AC bearings will be sold in pairs, or quads, which are individually custom ground so as to achieve perfect pre-load when rigidly fastened together with their "mates". With a single pair of unmatched bearings, you have to either shim and/or control the pre-load by how tightly you clamp them together. With two pairs of bearing, as you indicated, without the custom grinding, you'd have to shim them to get them all properly pre-loaded.
Regards,
Ray L.
Regards,
Ray L.