BC1.37 x 24T bottom bracket tapping tool Purpose and compatibility: Restores damaged threads in steel and aluminium bicycle frames to allow proper installation of bottom brackets that would be obstructed by worn or damaged threads. Efficient design: Features 8 deep chip removal slots that clear metal shavings during tapping, delivering smoother operation and reduced resistance for more effective bottom bracket thread restoration. Directional operation and guidance: Drive side requires clockwise rotation for thread removal and counterclockwise for thread inspection, while nondrive side uses clockwise inspection and counterclockwise removal. Clear instructions are included for proper use. construction: Made from aluminium alloy with speed steel cutting edges; workshopgrade tool weighing approximately 800 g; provides smooth tapping action with no burrs for clean, long lasting thread repairs. Use scenarios: damaged bottom bracket threads on a steel or aluminium frame to enable proper BB installation. Refurbish or rebuild a frame during maintenance to restore clean, functional threads before BB fitting. Perform drive side thread removal and nondrive side inspection/removal as required to ensure correct bottom bracket fit.