Comprehensive tool for BC37x24 threaded middle shafts. Designed to and rethread steel and aluminum alloy frames, this tapping tool enables seamless installation of the middle shaft. Effortless chip removal. Features 8 deep chip removal slots that facilitate the elimination of short chips, providing smoother operation and reduced resistance during use. Userfriendly operation. Engineered for ease of use; simply remove clockwise on the drive side and inspect teeth counterclockwise, a straightforward tapping process. Precise inspection methods. Nondrive side inspections are performed clockwise with removal counterclockwise, allowing meticulous checking and maintenance of your bike components. Applications Rethread damaged BC37x24 middle shaft threads on steel frames during installation. and rethread aluminum alloy frames to prepare for middle shaft replacement. Routine maintenance and inspection during middle shaft servicing to ensure proper seating and longevity of components.