Lathe lead screw question

[DPittman]

Yes I think I will try a larger dial eventually and making it will be a chance to do some indexing with my new dividing head maybe.
I have typically threaded as slow as I can (100 rpm)for ease sake but know with carbide inserts threads can be better with higher rpm. However, I have a variable speed motor and should be using that to adjust speed on the go....slow to start and pick up speed once engaged.

 

[DPittman]

So just in case anybody got confused like I did for a while, I want to state:

A larger thread indicator/chaser dial will not make it any easier to engage the half nuts at the right spot. Matter of fact it will make it harder as the circumference of the dial will be moving faster (think surface feet per minute). However the larger dial will make it easier to see if I am on the right spot or not.

 

[PeterT]

Just wondering when you engage, does it seem like it favors slipping in slightly ahead or slightly behind the line? Mine likes slightly behind but its consistent. I'm not sure if your lathe is like mine but if you ever see the back side its a bit underwhelming. Its been a while but I believe the brass nuts are retained by a screw, maybe alignment pin but I doubt it. So there could be some wiggle room of how it was assembled or maybe the assembly is drifting slightly, which affects clam shell engagement. I read on another forum where a guy had engagement issues & turns out his thread lead screw could be engaged in the headstock receptable 180-deg rotated which of course affects engagement timing. My roll pin centers are off center which I'm not sure is a quality issue or a design feature!

Lastly, I've learned that my lathe engages much smoother if I ease it in over a small time slice rather than trying to hit the line it bang on. Kind of hard to describe but like squeezing a trigger vs jerking it if that makes sense. I mean you cant be sloppy late or early but it just seems to work better with a deliberate, but ever so slightly slower engagement. Your mileage may vary.

 

[DPittman]

Just wondering when you engage, does it seem like it favors slipping in slightly ahead or slightly behind the line? Mine likes slightly behind but its consistent. I'm not sure if your lathe is like mine but if you ever see the back side its a bit underwhelming. Its been a while but I believe the brass nuts are retained by a screw, maybe alignment pin but I doubt it. So there could be some wiggle room of how it was assembled or maybe the assembly is drifting slightly, which affects clam shell engagement. I read on another forum where a guy had engagement issues & turns out his thread lead screw could be engaged in the headstock receptable 180-deg rotated which of course affects engagement timing. My roll pin centers are off center which I'm not sure is a quality issue or a design feature!

Lastly, I've learned that my lathe engages much smoother if I ease it in over a small time slice rather than trying to hit the line it bang on. Kind of hard to describe but like squeezing a trigger vs jerking it if that makes sense. I mean you cant be sloppy late or early but it just seems to work better with a deliberate, but ever so slightly slower engagement. Your mileage may vary.

Yes each lathe seems to have its own peculiarities in how to engage the half nuts on the mark (ok I've only ran 3 different ones in my life but they were different). Yes my thread dial indicator did seem to go to one or the other side of the indicator line when I was always trying to hit the line. But the other day I took it apart and by golly the dial is just held on with a screw pressure fit and can be adjusted! We'll that makes it easier but it is still a pretty fine line between being right on the line and just one thread off. I think I will eventually try a larger dial face, it's an easy thing to make and it's a project.