On 12/17/2010 04:00 AM, Karl Townsend wrote:

I needed this on my lathe spindle. Turns out there was no way to do it
in Galil/Camsoft (Let me know if EMC has a way)

As far as I know, EMC2 requires a real encoder with index on the
spindle, as it needs to accurately handle the reversal when doing rigid
tapping. Yes, this really doesn't apply to a lathe threading cycle,
but the EMC way is usually to go for mathematical purity and completeness.

Since most lathes have an extension at the rear of the spindle, it is
usually possible to rig an encoder there somehow, often using a timing
belt. I figured out how to do it on a Bridgeport 1J, where it is
practically impossible to add a sprocket to the spindle. I think the
same scheme could be used to put 3 sensors on a timing belt pulley or
gear as would almost always be found on the threading gear train of any
lathe that has a threading screw.

See http://pico-systems.com/bridge_spindle.html

Jon