Lead screw or thread dial not right?

ok, it is possible, but mine are not as pronounced.
I did multiple tests.
about to post a video, I had slight mis-track on my 3rd attempt. But very slight.

edit: it's loading now.
 
Check your geartrain backlash. With the lead screw engaged and the half nuts free, how much movement do you get from manually rocking the spindle and lead screw? No need to measure at this point, just see how much or little is there.
 
If your dialing in the .002" (mentioned in previous post) with the compound and then running in reverse and your scratches match, well you had .002 * sin (whatever angle your compound is) amount of backlash.
 
xr650rRider said:
If your dialing in the .002" (mentioned in previous post) with the compound and then running in reverse and your scratches match, well you had .002 * sin (whatever angle your compound is) amount of backlash.
Click to expand...
I honestly don't see how that follows. Care to explain your reasoning?

Now if the gears were not adjusted correctly and are too loose, or not fully engaged, I could see there might be a problem. In that case there would be a lot of gear backlash to take up. Typically we use something like a sheet of paper in between the gears to get close to the right amount of spacing. If the paper gets stuck, but not torn, it is about the right gear spacing. At least that is what I thought I learned from here.

If I were to guess, something is not quite put together correctly, or adjusted. That compounded with some errors in operation. I'm not sure if the OP is an experienced machinist or not. My most sincere apologies if that is incorrect, did not mean to offend. We are still solving a puzzle, trying to find the essential clues.
 
This looks like you have a badly worn half nut. Since it is a new machine, then it is fair to say your half nut was damaged in the fall.

The pitches are parallel, which eliminates all the gearing issues. I expect to see one of the half nut clamps bent, and that half nut to be badly damaged. You will need both sides of the half nut, and the clamps to refirb your apron. *IF* I'm correct. the only way to be sure is to disassemble the apron and remove the half nut clamps with the half nuts still in them. Once you have access to the half nuts, you will easily see if they are out of alignment, prior to disassembly.

The other higher possibility is that your half nut dovetails are cracked or broken. - I'd rather that it not be that one. the fix is much harder.
 
Dabbler got me thinking about the half nuts. I’m not sure if I picked the right PM machine equivalent to yours, but here is screen shot of the manual about adjusting the half nut gibs on the 1440GT. It looks like when threading in reverse, the half nuts are pressed up against the fixed dovetail, but when going forward, it would be against the adjustable one. I’m thinking if that is too loose, it could explain why threading works in one direction and not the other.

029E6054-C454-4E0F-9038-1BEC3E66C144.png
 
Ok, definitely something with the half-nut/split-nut. I adjusted the gib a bit tighter, and did the same test, I now have 3 lines, it split the difference between them....IMG_0122.jpeg
 
which gib did you tighten? if it was the cross slide, lock up the compound so it doesn't have any play... and try again.
 
You need to cut a full thread. Do not run it in reverse with the threads engaged. Back out then reverse. Go far enough back out to allow any backlash to be removed. If it will cut the threads correctly over all those passes. You may have fixed the issue with the half nut gib adjust. If notI think might you have something loose like your gibs or other components. Go through and make sure everything is tight and gibs adjusted correctly cross slide and compound.


Cutting oil is my blood.
 
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