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Apron Half Nut travel


Oct 25, 2016
I was getting ready to put the oil pump and sump back on the apron and re-attach the apron to the saddle but in checking the operation of everything else....

I cannot get the half nut operation to work properly now. Without the two side half nut brackets, I get full travel of the half nuts, including while using the push in knob (both preventing and allowing the travel).
As soon as I put the side brackets back on I only get half of the travel.

In BOTH cases, the small rectangular slotted piece that rides on the pin, does NOT ever travel to the upper left corner meaning the pin doesn't ever get to the top left corner, it can't because the lower half nuts travel is at is max while the pin is in the middle of the slot. It almost seems to me like this assembly is a combination of other lathes parts and not the originals as it doesn't seem to fit properly. The lack of proper feed, was part of the reason for the whole dis-assembly and rebuild of the apron. everything else with the apron works fine now.

I've spent a lot of time today trying to figure out why this isn't working but I can't come up with anything else to try other than finding a whole new half nut setup. See the attached videos, and yes I noticed the loose nut on the bottom half nut after reviewing the video, tightening it only made the travel worse.

Any recommendations welcomed.




Feb 23, 2016
Houston, TX
Is the longitudinal feed lever in neutral position ? The lever closest to hand wheel for traversing rack.

There should be a lock out mechanism to prevent both long feed and half nuts from engaging at the same time.

If long feed is in neutral, I'd be investigating the lock out pieces between it and half nuts to see if they are stuck, wrong position or whatever.

Typically pushing long feed lever down will slide something toward half nut, and raising long feed to neutral will withdraw the sliding piece away.

I think the knob you were pushing in vid is feed direction.


Hot Rolled
Apr 27, 2011
Central Wisconsin
There is a "neutral" detent in the middle of the fwd / rev shift knob travel that you must land on. That is the interlock! I had some troubles with this as well until I got it all cleaned and tuned up. It was easy to skip over the neutral position and prevent the half nuts from engaging. I forget the exact arrangement but somewhere in there is a ball and spring to facilitate the neutral position detent on the shift knob.