Summary

Though not owning a player piano, I've nonetheless dealt with a lot of old piano rolls in my hobby of scanning them to digital forms, including MIDI. Consequently, I've been aware that many roll enthusiasts, who in fact do own a player, are often frustrated by brittle, broken phenolic roll ends. This is not an attempt to one-up Ian Hamilton's design from a few months ago, but rather a first try at a parametric version to allow users to print a custom replacement roll end.

The roll end prints in two parts, and then the tube part is pressed into the flange part. Note that the top of the tube part has a very small chamfer to aid in centering. Some trimming may be necessary to make them fit together. The variable eps in the script adjusts the difference in diameter between the two parts. With the provided value and my printer, I have been able to trim the interior of the flange part minimally and then bang them together a piece of wood or similar. Also, if they're printed with ABS, a small amount of acetone can be applied with a small craft brush to the joint where they press together, cementing the joint quite strongly.

I found 30% infill to be adequately strong for the purpose. Slicer tells me that 4.5m of 1.75mm filament is needed for one end set. I generated no supports, since the tube side of the flange part can tolerate some drooping extrusion without interfering with the fit.