Guttermann (and others) sewing thread spool adapter

A very simple, but rather useful tool for your sewing machine: end for good the fall of oversized thread spools from your Singer or Pfaff sewing machine.
Those adapters will hold the large spools with no risk of falling and unravelling (or your cat start playing with…).
The 16.5mm OD will fit the 600mt Guttermann spools.

Easy-peasy

The ones for Singer domestic sewing machines have a ¼" (6.4mm) inner hole, the Pfaff type has a 4.1mm inner hole. Do a quick test, just stop the print after 4-5mm height have been printed, to check the dimensions are ok due to possible material shrinkage. You want to have a reasonable snug fit.