You are correct. In a former life that was fiberglass pc board. I used some etch to take off the copper.

The couplers are 2-56. I can make about 15-20 of them in an hour. The hardest part is getting the drill started. It wants to slip off to one side or the other of the rod. Once it gets started it cuts right through. These are tiny wire bits. It amazed me how easily they cut through that material.

So my question remains though. Do you think the PC board will cut through the pull cables?