Mary has been doing Ruler Quilting and wanted a pencil guide (similar to the machine’s ruler foot) to let her sketch layouts before committing stitches to fabric. The general idea is to offset the pencil by 1/4 inch from the edge of the ruler:
That was easy.
Print three to provide a bit of cooling time and let her pass ’em around at her next quilting bee:
Her favorite doodling pencil shoves a 0.9 mm lead through a 2 mm ferrule, so ream the center hole with a #44 drill (86 mil = 2.1 mm) to suit:
The outer perimeters have 64 facets, an unusually high number for my models, so they’re nice & smooth on the ruler. Even though I didn’t build them sequentially, they had zero perimeter zits and the OD came out 0.500 inch on the dot.
The chamfers guide the pencil point into the hole and provide a bit of relief for the pencil’s snout.
If I had a laser cutter, I could make special rulers for her, too …
The OpenSCAD source code as a GitHub Gist: