I bought some Filaments.ca spools, so I had to modify my endcaps for the bore of those spools.
There are two files here, because the rim of the bore in Filaments.ca filament spools have a wider tolerance than others, so if the cap-filmaentsca is just a little too small, you can try the cap-filamentsca_largerside.
So far, I've found this size works for the "Standard PLA" spools, both the 1kg and 2kg varieties.

The SCAD file requires the partial rotate extrude, which I linked to as a "remix".