Large Circle drawing Trammel Points

Update: As there was ongoing confusion about how to handle imperial units, I've uploaded STL files dimensioned in mm.

Trammel points for larger circles. Limited only by the steel rule you use. I found I needed to more frequently draw and cut out larger circles and arcs than I have templates for and which are too large for my drawing compasses. The radius setting can be read directly off the scale on the front of the pencil holder. Minimum radius is 1.25" and maximum is the length of the steel rule.

The drawing point uses a Pentel P205 (.5mm), P207 (.7mm), or P209 (.9mm) mechanical pencil as the drawing instrument. The pivot is a 1 inch nail with the head cut off and friction fit into a receiving hole in the fixture.

Hardware is 8-32 nuts and screws. I was going to use thumbscrews for the pencil end, but found it simple to adjust using a screwdriver. Backing off the screws slightly gives a good friction movement. The rule I used is 1.115 wide and .035 thick and I got t