還牙銼，0.7-3 mm 螺距

Finally, a thread file that actually matches the pitch markings, saved a 12mm bolt I thought was beyond repair. The file cut cleanly on the first stroke and the handle gave just enough grip for controlled pressure.

The file handled a slightly crushed 8mm bolt on my motorcycle skid plate without any trouble, the hardened teeth cut cleanly. It's a simple tool that does exactly what it's supposed to for fixing rusty threads.

Had a rusted bolt on my gate hinge that no wrench would touch, and this file cleaned the threads up in a couple minutes. The 0.7-3 mm pitch range covered everything I needed, from small bolts to a pipe fitting. Way cheaper than replacing the whole assembly.