Isn't it easier to just use a manual tap handle and turn it by hand? Whenever I'm tapping a hole, I use the tap handle. Once the threads bite, I turn it a fraction of a turn, then back it out and clean out the shavings, thread it back in and turn it some more. Kind of like tuning a piano, turn it a bit, then back it off a little, and periodically removing it completely and cleaning out the shavings. Do this until it's all the way in. Of course I use thread oil for steel and other hard metals. For softer materials like plastics, I have some other stuff that appears to be water-based, that more closely resembles soap and water. If I don't periodically clean the tap as I go as described above, eventually a shaving gets stuck in the threads and there goes the tap. It takes extreme care when tapping a hole that bottoms out in a thick piece without going all the way through, and you need a second tap to finish the job, one that's almost flat at the end, with only a few threads of taper. I forget what those are called. If you do break the tap, might as well throw that piece piece away and start over.