TB DRUM INSTRUCTIONS ATβ x 17x 217 insert (287 & 327) To assemble drum carrier the 3/8β B. 17x 1" x 28β insert (367 & 407) washer should be placed on the bolt of C. Bottom Frame of Drum the knob. Then screw the knob into insert threads. (Picture Below) , C, and either insert A or insert B depending on size of Drum then tighten both set screws on frame C.