Chamfered Polargraph Line Spool
A 42 mm dia x 44 mm line spool from the 'NEMA17 Hanging Wall Polargraph Drawbot' kit (print two). It has a 30 mm drum that takes up 94.2 mm of line per turn, a 5.2 mm bore for the NEMA17's 5 mm shaft, and a radial 4.0 mm bore for an M3 heat-set insert and set screw. A 2 mm anchor hole in the outer flange holds the line. Both flanges are 45° cones, so it prints without supports, and a hollowed core keeps it to about 25 cm³.
robotics kit polargraph nema17