When repairing the coolant heater hose on a 94 GMC K1500 this aluminum fitting broke off inside the upper manifold. So I had to grind out what I could and then tap the threads back to normal with this. It worked flawlessly and easily. It never binded and I was never concerned on it breaking. The tap seems of high quality and very sharp. I was even able to put test threads in a block of wood to be sure I had the right fitting before using this tap and it gracefully threaded a 2x4 as well.