Inspired by the Mastercraft winder I tried to use its principle for a „quick and dirty“ mainspring winder. The spring I used for testing has an arbor diameter of 2,2mm (left wound) and the barrel has an ID of 8mm. The mainspring has a hight of 1,2mm. So I found a washer with the right thickness of 1,2mm, drilled it to 7,5mm ID and cut a slot in with my dremel. Then the washer was fixed to a board with three tiny drops of super glue. I used the original lid and arbor and my pin vice to compl