Gridfinity Holder for Drilling Cup

These plastic cups hold interchangeable drill bushings of different sizes, and are commonly used in aircraft sheet metal work.  The purpose is to help ensure perpendicular holes when used in situ, because it's rare when you can take a drill press to the work or vice-versa.

One of these will just barely fit into a single Gridfinity square, which led to some artifacts on the side of the holder even when printed with a 0.4mm nozzle (I usually use 0.6mm for Gridfinity).  

Like my other Gridfinity models, the bases are altered to accept 6x3 magnets as a press fit, with the upper surface of the magnet holes modified to make the slicer bridge across correctly for a clean result.  The unit pictured was printed out of Polymaker matte blue PLA on a Bear upgraded Mk3S+, using a 0.4mm nozzle at 0.2mm layer height.