Lectric XP - Correct Threading Die

Your fork must not have been hardened steel. For my old Trek 800. I had an RST Capa 1" threaded suspension fork, just a run of the mill $89 fork. Needed to cut about 2" of threads on it,. The shop wouldn't touch it. Said I had to have bought the fork from them.
I bought an amazon die, around $39-49. The thread was just common. I saw why the shops wouldn't touch it, The die wouldn't cut thru that RST fork. It was plated, and pehaps that made it harder, but it would cut a cheap kids fork I took off an old bike,
A happy solution was that I had plenty of unthreaded stem on the fork, enough to cut it all off and convert what was left to a 1" threadless mount. You don't put a threadless collar on the threaded part of a fork,.Too weak.

Here check this out, this guy used a non threaded same model necco headset that fit with the top part that was threaded if I understand everything correctly.