I'm a little late to the party, but I finally had some time to create my
own version of a solid model for a music roll end, which you can see at
https://www.thingiverse.com/thing:4879571 and from where you can download
it. The OpenSCAD script describes a roll end modeled on the dimensions of
the old phenolic QRS roll ends, but the script can be edited as desired
to arrive at a roll end of custom dimensions.

Marshall Jose

 [ Ref. https://www.mmdigest.com/Archives/KWIC/Numbers/3d.html 
 [ -- Robbie