This Master Craft Mainspring Winder has been recommended and praised several times by @clockboy and I’m so happy that I, after several years of trying to acquire one, finally found a copy in very good condition on eBay. The Master Craft mainspring winder is surprisingly easy and convenient to use, and of the mainspring winder variants that I have tried so far, K&D 128, and Bergeon style winders, I must say that the Master Craft winder is the one that I now prefer with a good margin.