42" Rotary Grinder Tool Flexible Flex Shaft Fits Dremel; This is a 42" grinder attachment which fits the majority of rotary tools. connection is for head with 3/4" (19.05mm) thread. Work with the Dremel 100, 200, 300, 3000, 4000, 7300, 7700; Foredom, ToolShop, Performax, Milwaukee M12, etc.