I've been busy sorting Misha's stuff and often just too tired or mentally weary to do much in the shop so it's been somewhat incremental.
The shaft is 0.75" (or so).
The shoulder is 0.875" which is supposed to be the peak of the 20 TPI thread. I also cut a slight groove to point out where the edge of the cutting tool is. I set my ELS END position to this point.
No picture but next I used the parting tool to cut runout groove to the depth of the thread. That didn't work out well because the parting tool was sloped downwards to the left so the left side of the slot wasn't as deep as the right side. Ah well.
I did start making a video. Did a nice first pass and then in the process of holding onto the camera trying to keep it aimed at the various items I pressed START without following the instructions on the screen to withdraw the tool. No matter. The first cut wasn't that deep so it didn't really affect the final product.
Anyway, made a much shorter one and now it shows just the final passes. Notice on the left the nut is held in place there for trial fittings. I had to take the part off the spindle drive after carefully scribing where it was and then putting it back.
But. No matter how many passes I couldn't get the nut to thread on.
So I pulled off the centers, installed the 4-jaw, centered the nut and then with a bit of difficulty got the ELS to line up the boring threading tool to line up with the threads. I then just kept going deeper testing with the now threaded arbor until it turned on smoothly.
And flush against the shoulder.
Next I need to turn it between centers again and cut the 1" diameter shoulder to register the blade and the nut.
Maybe tonight.