"Whenever you’re faced with dirty or slightly burred female threads (cylinder head threaded holes in a block, spark plug holes in a head, etc.), you may be tempted to grab an appropriate size cutting tap to clean up the threads. The correct choice is to use a “chaser” tap. A cutting tap is designed to create new threads, whereas a chaser tap is designed to clean, re-form and restore existing threads."
https://www.summitracing.com/parts/...Q7eHL5AIVuSCtBh28YwNjEAQYASABEgKgTPD_BwE Exactly. That is what you want to use to clean every thread before assembly. And to find out if there is a problem. Taps are to cut threads and I don't want to remove material unless the thread needs repair. But you still will want a complete tap and die set and bottoming taps for other thread repairs. Even a HF set will work and last the rest of your life.
(OK, I'll admit I have a tool fetish. But when I need something, I have it.)
