Got back from a business trip to Nashville (and a stop ay my brother's place in Durham NC on the way back) yesterday, headed to the shop today to try and salvage the screw I had started making for Darren. No hope, as the threading insert had dug in too deep on the load side of the thread flank. And that was my second attempt.

Third time a charm, thankfully!

As I'd done with my second attempt, I first turned a wide groove in the area of where the gear will eventually sit. This gives me a generous landing spot for pulling out the half nut while threading a 5 thread per inch thread at 120 rpm.

Here's a shot of the piece after I finished threading and before I cleaned the coolant out of it:


This close-up shot is so detailed it looks somewhat rough, but it really is quite nice and not a trace of chatter despite the 18.7" of thread length. My machine doesn't have a follower rest, so that's hard to do!


Here's a shot of the three flats I had first milled on the end going in the 3-jaw chuck. When I made my first attempt, the finished 20mm diameter spun in the chuck from having too much tool pressure as I threaded. I probably should have cleaned off the cosmolene gunk from the 8 year old (but still new) 12" 4-jaw independent chuck I have that's never been on the machine. Too lazy to drag it out when this worked fine both times.


I'm just happy to have this part of the project done, finally! Finishing up the diameters, thread and keyways will be simple, despite the interrupted first cut I'll have.

I think I'll leave it as is and start on the mating bronze nut. This way I won't worry about damaging the finished 20mm diameter nor the M12x1.75 thread.