I enjoy making illuminated borders and drawings inspired by medieval manuscripts, but the escutcheon (shield) shape used for heraldic devices always gives me headaches. In the past, I've used a printout of various escutcheon sizes and a light box to trace out the symmetry and curves, but that's not always possible in various situations, or with thicker paper stock. I've wanted to make a template for a while, so I sat down and threw one together.
This is a simple drawing template for layout of scrolls, awards, and other things needing an escutcheon shape that you don't want to draw freehand. It uses the "1/3rd radius" construction method commonly used in SCA documents. It contains eleven different graduated sizes from 14mm to 50mm tall (about 1/2" to 2" high).
As designed, it is 2mm thick, with undercuts around the outside of the template to assist in picking it up, but NOT in the shield shapes themselves. Thus, it is suitable for use with pencils, silverpoint, and styli, but ink would probably wick under the edge and ruin everything.
This is a fairly quick-and-dirty design, spun up in OpenSCAD. I ran a copy off in PLA on a new Prusa i3 MK2s that hasn't really been dialed in yet, but it did just fine. As long as you can print a thin, flat object measuring about 175mm x 90mm x 2mm thick, then it shouldn't pose too much of a problem. The chamfered edge is a 45 degree angle 1mm thick, and is non-critical to the design, so it shouldn't need any support, or affect its use in any case.