I haven't broken my Harbor-kluge tool yet after several bb rebuilds, but when it seems like I'm having to turn the wrench particularly hard, I'll start over after first blasting the crank with a propane torch for a minute and a half, or until some smoke starts just drifting off of it.

For the golf-tee pin, I shortened the thin section and reinforced it with a same-length alloy sleeve, also adding a washer to allow freer rotation.

Mine also got some grinding with a carbide cutter to more-easily fit the cranks that I was attacking.

I also remember encountering what seemed like hardened steel when drilling out the opening in the main driver, so I recommend a heavy drill hand on a securely anchored driver in the vise, drilled at modest speed using cutting lubricant.