I have used this for quite a while now and yes, it's a VERY handy tool to have for quick locations on sheet material and or picking up edges.
The smallest I could get mine was .010" of an inch which is not too shabby but I'd like to know more about your polarizing filter and what you used. I have a glass one from an old camera but haven't cut it yet, may I ask what you used?
The sort of Delrin clamp I used has a through hole for the body and a counterbore for the knurled part and is pushed up into the counterbore and then locked down with the screw so it can't vibrate loose. I actually moved it since these pics were taken, over to the right side of the headstock to get it "out of the way".
I have it powered with a wall wart AC adapter and has been working for a little over a year now.
Thanks for sharing-
Dave


