New Member and Mk2 Half nut cam question

[Machine_Ed]

New member here, I found the forum here while searching for some issues on my Atlas 6" Mk2 Lathe (Model 3950). I've had it for about 35-40 years, my uncle had originally bought it new from Atlas in the late 1970's. Sometime back in the early to mid 2000's I went through it and completely overhauled it and it still sees occasional use, although I don't get to use it as much as I'd like to. It's the early version without the carriage feed backlash adjustment.

About a month ago, I went to use it and realized the half nut lever was barely able to be moved, which I figured was old lubricant and not seeing enough use. An internet search brought me here, and I was able to disassemble all the parts which I'm in the process of cleaning up to remove the gummed up grease. I can see the line from the ball bearing that provides a detent for the half nut operation, but I don't see a recess for the ball to drop into other than the slots that engage the pins on the backs of the two half nuts. It's been a while and I just can't remember how positive a detent there is on the half nut lever operation, other than you can only move it as far as the pins on the half nut will let you.

Am I just overthinking things here, after all it's worked fine all these years.

Ed

 

[markba633csi]

I think it's a design error, my detent didn't seem to work either but the lever stays where I put it- not sure how

 

[benmychree]

Could be that the ball just provides enough friction/drag to keep the half nut from engaging itself; having a true detent might not be the best thing.

 

[Machine_Ed]

Could be that the ball just provides enough friction/drag to keep the half nut from engaging itself; having a true detent might not be the best thing.

That may make the most sense, as if there was a deeper detent, they probably would have used a longer spring behind the ball, it is fairly short.

Ed

 

[RandyM]

I find that I kinda ride the half nut lever on my Logan when I am threading. My Logan only has the weight of the lever to keep it engaged. And even then, the lever really doesn't have a lot of weight to it.