My wife is an artist, and sometimes wants to draw large circles on a canvas. So I made her this beam compass. It uses a $1 Lowe's Wooden Yard Stick as the beam. (Lowes Item #22079 Model #30060)

You will need these parts:

• 1x Lowe's Wooden Yard Stick (6.4 mm x 36.4 mm cross-section)

• 1x 4d 1-1/2" smooth box nail (or something close)

• 2x 4mm nut

• 2x 4mm x 20mm socket head cap screw (1x 16mm and 1x 20mm is ideal)

• 1x 4mm washer

• and a pencil

To install the nail and the cap screws, I heated them enough to melt the PLA and then pushed them into place. They all retained nicely that way. Or you could drill-out the holes a bit and then glue them in.

If you want the imprinted yardstick measurements to indicate the radius of the circle, then cut the first 1 inch off the yardstick. (Or keep the yardstick full length and subtract 1 inch from from whatever is indicated.)

If you have a 5 gallon paint stick, try this design instead

Notes:

I used supports on the part that holds the nail, but only where it touches the build plate (an option in Cura).

I did not use supports on the part that holds the pencil. However, I rotated it 90 deg so that the slot cut along its length was on the print bed. With that orientation, it prints well without any support.