A bottoming tap is straight threaded and meant for blind holes. What HR is talking about is making the threads a bit wider so you have more thread engagement on pipe fittings. Useful if the mating fitting or pipe threads don’t have enough thread or not made deep enough.
If you grind a starting (straight threaded, ex. SAE) tap down you can make it into a bottoming tap.
Last edited by Phak1; 05/29/2020 10:16 PM.
