Quote Originally Posted by carl blum View Post
Hello Toolmaker51:

The drill motor only has a 1/4" chuck and I have only used it to tap in plastic. It will tap 1/4-20 through 1/4" PVC just fine. I might have tapped 8-32 in steel, but I don't remember.
Carl.
That limitation doesn't detract from the design and reversing mechanism. The benefit I see is not requiring or obstructing a machine spindle; whole thing could be purpose-built; and there are a LOT of more powerful suitable motors. That creates options in the various chuck mounts.
Any bench tapping I've used were suspended by a parallelogram maintaining tool perpendicular to work surface, nice but a lot of motion navigating hole to hole. Most tapping is a couple fixed locations on successive parts. Moving the part to a specific location needs no [or very little] coordination.