Poteniometer For Russian Big Muff - Work-alike
CTS 270 series. As purchased, the shaft is too long and full-round. But if you have a Dremel tool with a cutoff wheel (USE WITH CAUTION!), cut down the shaft to 1/4" long, grind to make the "D" shape and ream out slightly the hole for the bushing. One of my customers did this repair, and it works. See the detail pic.