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Paul,

The Variac is upside down in the picture and the metal plate that has the plastic screw in it is the rotating piece that the brush assembly is attached to - - better view of the plastic screw is in the last picture.

>mount something to the box in such a way that a stopping device could project into the brush path without touching the windings<

The small variacs such as yours (same as I use for fan control on my P1) don't have all the extra structural components. If I were going to persue this course of action, I would think in terms of a slotted dial on the front of the box with a screw into the box to disallow twisting it past a certain point, or something similar.

Don't take chances with the small variac - when you find a P1, You'll need it for fan control - works great.

I had to buy an EBay P1 recently to build a roaster for a friend. It's disgusting to pay $30 + S&H. Someone scored one the following day for $15 (my normal run of luck).

Mike
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