Worked great for cleaning rusty threads on a Laycock-DeNormanville Compact A-Type Overdrive Output Shaft that has been outdoors and exposed to the elements. The cotter pin was completely rusted so I had to break it and use a percussion tool to remove the castle nut which could be removed by hand once loosened. Needless to say, the threads were a rusty, damaged mess. The output shaft on them is part of the annulus and is difficult to replace and hard to find. I'd be pretty shocked if this matrix didn't erase it. I generously coated the threads with Tap Magic cutting oil and carefully and slowly screwed this die in by hand. After tightening it up and down a few times I'm happy to report that the threads are now in good condition. The nut is easy to turn by hand to the stop - just as it should be. This cute little stamp saved my sanity and a very expensive vintage part!