Park tool bottom bracket tapping facing set bts1the bts 1 is a precision tool system which provides a piloted means of tapping the threads in the bottom bracket shell of a frame after tapping the taps act as guides to keep the included facing cutter perfectly square with the axis of the bottom bracket for cleanup of the faces of the bottom bracket shell featuresthe bts 1 includes english taps 1370 x 24 tpi right hand thread for the adjustable cup and 1370 x 24 tpi left hand thread fo