You can get the Hozan tool for $145 from some place back east. Also shows up on fleabay around $50-75. I've got a brand-new unused one if anyone offers $100+shipping.

I've cut several thousand spokes on one back when I was a student building wheels for the university team. It does work well if you leave 2-3 of the existing threads as a guide when cutting down spokes. With bare spokes, you'll want to bevel the ends by about 1mm to help the rollers work up gradually. Otherwise, you may roll a ring that connects with itself. You're trading muscle and time for low-cost and you can do a set of spokes for 2-wheels in about 30-40 minutes.

We had a Phil tool at local wheel-building shop where I helped out occasionally. That tool is very powerful! However, it doesn't care about existing threads and will start its own threads when and where it wants. Looking closely with a magnifying glass, sometimes you can see existing threads split in half by the Phil tool at the ends before it re-forms them to new full-threads. So it's best to feed the Phil tool bare spokes. Can do spokes for 2-wheels in about 10-15 minutes.

In the OP's case, if it's just 2mm, I'd just trim the ends off on a grinder and slightly bevel the ends so there's no fragments. Much easier than re-treading with any tool.

BTW, there's a cutting die, such as with a tap & die set. And there's also rolling dies, used to roll threads.