Sherline mill CNC mods?

Hi all!

I've added constant-force springs to counterbalance my Sherline's head

(http://www.egroups.com/files/sherline/Head+counterbalance+springs/
for any of you on the Sherline group)

Next, I'm ready to tackle the conversion to CNC. It looks to me like the
main mechanical requirements are

1) Preloaded bearings for the leadscrews--Sherline's motor mounts
incorporate these, but it doesn't look like any of the other off-the-shelf
conversions do.

2) Adequately-sized steppers--100+ oz-in, from what I gather.

3) Minimal backlash on the leadscrew nuts--since the Sherline is too small
to retrofit ball or Kerk screws, it appears that making Moglice nuts for
the existing screws might be the best way to minimize backlash.

Does that cover it? I know that adding end-of-travel microswitches is good
for peace of mind, but I'm thinking about the mechanism itself for now. I
have the 5400 with spacer block and resettable handwheels, which I'll
obviously keep...

I'll appreciate any what-I-like-best-about-my-conversion or
what-I'd-do-differently anecdotes too.

Thanks!

Randy

Randy Gordon-Gilmore ,----.___________ ______________ _________________
ProtoTrains // = = === == || == == == = || == == == = == =|
Rio Vista, CA, USA /-O==O------------o==o------------o==o-----------o==o-'
zephyrus@... http://www.rickadee.net/~zephyrus