Good to know that the page loaded faster 
Like I mentioned the groove on the body was not deep enough for the cable. When I tried to insert a battery into the tube it got stuck, so I had to make it a little bit deeper. What happened was that the tool I made got pressed away after a few millimetres into the material (I suspect that my lathe wasn’t sturdy enough there). Well, after wondering how to best to it I decided to use my milling machine/ drill press to deepen the groove. First put the head together with the body into my rotary table. I also measured the deviation in the x and y direction:
To my surprise it was less then 0.01 millimetres right from the start (my rotary table isn’t very good. That was kind of a bad deal I made there), which was fine:
Next I noticed that I didn’t turn the grooving/ threading tool down to a specific diameter, since it didn’t fit in any of my collets. So I turned the diameter down to 16 millimetres:
Now it fitted in the collet:
I used the fence, so I didn’t hammer into the head and in the worst case break the blade:
Turns out that it worked very nicely:
I should have done it that way right from the start that would have saved me some time. But well, as long as it turned out fine.
That’s it for today, thanks for reading. Soon I will be done with the mechanical stuff, then I have to go on with the driver, the switch and the firmware