Light Machine Corp. Benchman XTr (retrofit)

Your spindle is the version that takes a custom straight shank toolholder. The hole you see is for a screw that secures the toolholder so that it cannot spin if the workload becomes heavy. The index for the spindle is inside the head of the spindle. I believe the index is a flat on the shaft. I wish I remember more, but my discipline is electrical. Intelitek should be able to help you. Are you still running the Intelitek S/W or moving to something else.

OK, I dug into the bowels of the spindle head to try to determine why the sensor was not reading anything. I removed the sensor and examined the spindle it was closest to. I bench tested the sensor and found that it did not react to a ferric metal mass. For fun I tried a magnet and it DID react to that. However the spindle parts show no magnetism at all. Is there any possibility a magnet was at some point glued to the washer? Non of my findings make sense.

Possibly it is a sensor similar to this one in design:
www.allegromicro.com/~/media/Files/Datas...A9D70FB340EE44BA4F1E
And the internal magnet has been destroyed by heat.

It is probably not worth worrying about if the thread is M8 x 1 or another of the common proximity sensor sizes, just buy an inductive sensor from eBay that _will_ detect the spindle.

[edit] But make sure that you won't run up against any frequency / response-time limits.

Thinking about it some more, I believe that is the drawbar sensor and not the spindle index sensor. The drawbar sensor is to ensure that the spindle cannot turn while the drawbar is open. The spindle index sensor is part of the spindle encoder connection to the speed control.

OK, That makes all kinds of sense now! That being said I think the encoder is attached to the back of the motor so that means the ratio must be 1:1 to be able to accurately index the spindle. I'll have to see if I can access the wires and throw a meter on them. Wow this is going to be a complicated series of moves. Well at least I have a direction to try. THANKS ALL!

It may be 1:1, if your spindle is 5K it is 1:1, if you have a 7.5K spindle, it is belt driven and it becomes 1.5:1.