Engaging the half nut - am I doing it right?

Morgan RedHawk

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I made an attempt at single point threading this weekend, and the results were not great, but better than previous attempts. I am using a PM1236 with a thread dial.

My question is this:
When my number is coming around, in order to make sure the engages on the number, I put a little pressure on the lever just before the number is up (kinda like you would do a stick shift if you were shifting with no clutch), not enough to grind, just enough so that when the threads on the lead screw align with the threads on the half nut it engages. Is this the right or wrong way to do it? I have not done it but a couple of times, and just want to make sure I am not going to tear something up.

Any advice would be appreciated (especially the right way if this is not it).

Thanks yall!
Morgan
 
You aren't going to strip a gear like you might in a automobile transmission cause no clutch is required. If you are more comfortable engaging the half nuts in that manner, then there is absolutely nothing wrong with it and you won't hurt anything.

Pat
 
Perfectly fine doing it like that. I do it that way on my PM1236 also & every lathe I used to single point threads with.
 
I just let my hand drag on the lever and it finally drops into place with slight additional pressure
 
It is possible to lean on the half-nut lever hard enough to drag the carriage along with the lead screw, even if it is just riding on the crest of the screw. I think most of us do what you are talking about, but apply just a little pressure so we can feel the screw and we develop a feel for when things are in line. Most of the thread dials I have seen seen to track slow to the screw, making it appear that you drop the lever a little early. Some of this is from wear, some from adjustment. It's just something to get used to in most cases, although if it appears that the index line is not aligned with a number/letter.....my advice is to work on it. You're asking for problems otherwise.
 
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