Review on HOZAN C 401 Thread Cleaning Compatibility by Eric Power

They are beautifully made. Like jewels and as sharp as possible. The guide grooves help start straight, but a large amount of cutting oil or other lubricant is a must. If you're just cleaning an existing thread some bike lube works great, but if you're cutting new threads use cutting oil. These taps are ideal for aluminum cranks but require extra care and attention when working with steel. When tapping a new thread, you should always turn forward about 1/2 turn and then back 1/4 turn to clear the chips. It takes a while, but works great. Since 99% of hand taps are used to "twist" existing threads, I think they will last two lifetimes.