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 three of different lengths inexpensively here: https://www.amazon.com/gp/product/B071H4XCDW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1.
Simple supports needed only for the pivot end head. Pencil cavity can be down and does not require supports. PETG works very well with good sizing for nuts and screw shafts. I assume PLA will work very well also.
Cut the head off a 1" finish nail and insert into the pivot hole. It will push in 1/2" leaving 1/2" exposed, which matches the extension of the pencil.
I used a small piece of double sticky tape on the end of the rule at the pivot en to make sure it did not move off the pivot alignment.