No vibration. We have the gullets in the tap that separate the teeth. The length of the teeth is fairly short, so yes there is a small helix angle and there probably is a little binding during the cut, but I didn't have any issues. Look at a thread milling cutter, its like I have 6 of them cutting at the same time.Each row of teeth will be offset from the previous row by the thread pitch divided by the number of flutes.
What I want to know is how he stops it from vibrating like crazy as each flute tries to climb its own cut!