Trammel with Pencil Holder

A trammel is a tool for accurately laying out large circles and arcs. It consists of two holders for scribers that can be moved along a bar. This design is based off of a design by http://www.thingiverse.com/araspitfire, http://www.thingiverse.com/thing:4206.



I wanted a set of trammel points that would work with a 1/4 inch bar and 6-32 hardware. Also, I wanted a pencil for one of the points for marking wood and paper.



Note - I would be glad to make a metric hardware design of this if s