Not 'stupids' at all Marv. It took a little bit to get my head around it.
The only problem is that it will only work on a machine where you can reverse the the whole machine including rotation of the chuck.
Just to explain basically how it SHOULD work.
There is no manual retracting of the cutter at all.
As you know, under certain conditions, you have to leave the leadscrew engaged when cutting threads, on my machine, whenever I cut Imperial threads. When you cannot use the drop in dial.
You take a threading cut as normal, when you reach the end where you usually retract the tool with the cross slide, you don't retract, you just put the machine into reverse, to take the tool back to the beginning. As the tool starts to go back along the thread just cut, because the chuck is running in reverse, the tip of the tool is lifted by the non cutting action. It should only be a few thou lift, that bit has to be tried out yet.
When it reaches the start point again, the tip should automatically drop to the cutting position, so another cut is put on with the compound and run in the normal way. It should work for cutting both right and left hand threads.
If it works, it saves having to retract the tool, and then reset it to zero each time. It does away completely with that part of the cutting regime.
Not a very good explanation Marv, but I hope it strikes a light.
All we need now is to see the work wasn't all in vain. If it doesn't work, shrug shoulders, at least we tried.
John