Single point threading problem

[Mayhem]

Quick update. Well I reground the tool with an increased side relief angle and it did much the same on the original piece that was problematic. I think the metal is too low a quality (was a boiler plate slug), as the tool tears more than it cuts (despite being sharp).

I had an old drill coupler that was given to me by the previous owner. This was very hard and had to be annealed but finishes much nicer. The threading tool was cutting quite well in this, although the finish wasn't as nice as I would have liked but may have gotten better as I approached final dimension, taking finer cuts. However, I never got that far!

The thread dial stopped working (I'll address this in another post), so I left the half nuts engaged and simply backed the carriage up after each pass. After several passes the thread was forming nicely and I was backing the carriage up when it suddenly stopped. The spindle was spinning but not the leadscrew. One of the change gears has walked Given that I was turning a 6tpi thread, my lathe only requires 1 quadrant gear and I did think at the time that I should make a spacer as the shaft is sized to accommodate two gears.

I did try to pick up thread again but failed. Oh well, you live and learn!