Tapmatic power tapper for 10 bucks. Not quite but close.

[Moldyjim]

Went and grabbed mine from my tool box.
It's a #4000T
When feeding down you grab the lower housing, let go and it quits spinning the tap.
Pull up a little and hold the top housing and it reverses.
No on/off needed.
It came in a (homemade?) wooden box with 3 different collets and adaptors for attachment.