Guys, for my reprap I want/need to hob a 6mm bar with an m3 tap to create something like this:

In all honesty, the profile of the hob is relevantly unimportant, the idea is that it chews up the bolt enough that when a piece of 3mm PLA filament plastic is pushed against the hobbed section, it grips it and pulls it around with it. The M3 profile simply matches the 3mm filament size, really the chewed section is the important bit. I'm just generating teeth to dig into the plastic.
I've no doubt I could do this without posting but although I have the equipment, I don't always use it in the most useful way so thought I'd post up before setting out.
I could cut it like a pinion for a clock - most of you know my exploration in clock making. But this is tricky setup as I'd have to cut a cutter!
If I hobbed, I'm guessing I'd need to make a rolling fixture to allow the hobbed bolt to turn. Could I make use of my CNC rotary table on continuous turn at aprox 15rpm and offer it upto the tap mounted in the spindle and allow the rotary table to drag the tap around in the unpowered spindle?
Other than that, I guess it requires a supporting fixture.
Ideas welcome!
Chris