Eric, many years ago in the UK, I sometimes gave a hand to a guy who had a business making brass earth wire connecting blocks, like the plastic "chocolate block" type but solid brass instead, each with 5 holes across and 5 pairs of 1/8" tapped holes on top for the screws that clamp the wires, they were held in hardened steel jig boxes, first drilling all the holes, then tapping with a small (very old) tapping machine that looked like it worked on the same principle as the attachment from your link, I was paid 25 pence for each one and going at it hard ,I could do 1000 in an 8 hour day, 10,000 tapped holes!, very boring (no pun intended!) but £25.00 was quite a lot in those days so it was worth it!, we used to have to change the drill bits quite often but I can't remember how long the taps lasted, anyway the tapping machine worked a treat and never broke down as far as I can remember, so I would give that one a try, it looks like a good price!
Giles