On Thursday, April 4, 2013 5:34:25 AM UTC-4, wrote:
Thanks. I think that LV or needle bearings would not work on this small size. I appreciate the advice against using brass and bronze together. I think I'll go with a delrin sleeve and brass shaft.

Lostfr,

Hate to be a pest but...

Needle bearings are compact enough to easily increase your shaft size to 5/16" in a 1" brass pulley. They come as small as 3/16" IIRC. Look at Timken's references.

Use drill rod for a 5/16 threaded shaft. 3/8" dia. brass screw-on end-caps for finals/width adjustment spacers. Saves customer's cutting & polishing work installing. A 3/8 hole is almost same as 9.5mm. Works worldwide, no need to send a 1/4" drill with the kit! That saves you cost.

Delrin on brass may creep over time under high static load. Keeping C-string in-tune may be harder. Hate to see your nice C-extensions compromised with a poor bearing choice.

How come this is such a cost-sensitive problem for you? A C-extension is many hundreds of dollars to install, no? You need lower-cost CNC machined parts? If so I may be able to help. I like interesting side work. Small runs are no problem on my gang-tool lathes.

Good luck.

--

PaulS