Reflective pickup

Can anyone on the list give me a suggested part numbet to add a pick up on a
Sherline lathe for TurboCNC threading.
I don't want to use a tab on the Sherline pulley due to the danger it would
present.
I am looking for something that can see either a reflective or a BLACK spot
with mimimial dimensions, working distance in the range of 1/4" to 1/2" +
range.
I want the type that will sense off the end or side of the device, but not
the type that has a U shape with pickup between the U sides.
Or if you have done this to a Sherline, Please describe what you did, and
what part/parts you used. And would you do it the same way again?
Any suggestions would be greatly appreciated.
Thank You,
bill

Cross posted to other groups.


[Non-text portions of this message have been removed]