"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley
in . 3.70:

My bet is, if it's working reliably at 500 rpm, it'll probably be fine
at 4K.


I should have added that back in my "robotics" days, I hand-built quite a
number of quadrature encoders, with a few sporting 8K counts/rev, and
never had any problems making them work. At the time, all I had was a
fairly worn out Atlas 6x18 and a drill press.

I relied on a local photo-engraver to do reductions of my full-up
30"x30" drawings of the grating wheels. Inking the damned drawing on a
2K-spoke wheel was more work than any other part!

LLoyd