Ok her we go again
For the spindle I used a bit of 12 mm mild steel bar, because I will be working over a relatively long length, I decided to screw cut the threads (5\16 * 32 TPI ME and 1/4 * 40 TPI ME) to get things going straight and clean up with a die, a bit of a cheat.
My lathe has a metric screw thread so you have to set the gear chain up with a 125/127 change gear, these are the gears

the change gear is the one in the middle
And the gear train in the lathe, what your basically doing is linking the spindle up with the lead screw so that the two turn in a relationship thats gives you your thread pitch

And this is the lathe set up, because my lathe doesn't have a split nut, it stays engaged all the time, and the slowest speed I can set my lathe to is 70 RPM when working up to a shoulder its easyer to have the lathe in revers, with the tool at the back and to cut left to right away from the chuck.

I also put a 5 mm length M5 thread on the end to take a turning knob.
The other bits were just plain milling and drilling.
Two small bits of 3mm guides of silver steel were stuck in place with Loctite to a

This is it nearly finished I used a bit of hex loctited to the spindle for the handle from Marv's thread one flat would equal 0.001" ish

I thought of using a ball bearing for as an anvil but don't know how to fix it, as anyone got a 3/8" ish ball with a hole in it ?.
Cheers
Stew