For cutting 1-3/8 x 24 threads in T6061 aluminum when machining two freewheel adapters for my homemade tricycle. It seems to cut well and the threads work perfectly. I used an aluminum type thread lubricant which cuts threads better than dry thread. This was the first time I actually used my 1949 South Bend Model C for threading. I ordered this because I didn't have threading tools and didn't want to spend a fortune on something I wouldn't use often. But it should be good to use for quite a while until I chip it.