Help Logan 2557v crossfeed sticky

I'm working on a Logan 2557 12" lathe. It has the taper attachment, which requires a longer crossfeed screw. It came from a high school, and the hand crossfeed screw assembly was bent - the linkage through the hand crank to the crossfeed screw, Logan calls it the crossfeed sleeve gear. The crossfeed screw itself is ok, at least not visibly worn or bent. The hand crank turned ok, but not concentric.

I plan to replace the bent part of the crossfeed sleeve gear, but first I just improved the conentricity of the hand crossfeed assembly by bending the bent part back, and I cleaned everything up. I used a dial indicator and rotated the part to determine where and how much to bend it. I used a vise with 3 round bars to do that. It's not ideal, but the dial no longer appears to wobble as the hand crossfeed is rotated. But now I have a new issue.

The crossfeed screw is secured at the far end with a simple washer and nut. After cleaning and oiling, the nut has begun tightening down randomly when I turn the crossfeed, locking the hand crank. I put up with that wobbly crossfeed for 5 years, and the thing always turned smoothly. I wonder if the nut was too gunked up to be able to tighten down before? Am I supposed to thread lock it in place? I can't figure out why it ever turned smoothly before I straightened and cleaned the assembly? I looked over the diagram, can't find any missing parts. Any ideas about what I'm screwing up? I think I must be missing something very basic. I thought I could set the nut position with a second nut, but just wanted to see if anyone else has one of these can help or if someone can explain it to me.

Without seeing a parts diagram I'm just guessing, but if the nut on the end of the leadscrew is adjusted to take up the backlash between the screw and the taper attachment, I would expect to see a locknut to hold that position. That's the arrangement for the simpler situation with no taper attachment. The leadscrew is anchored at the apron on order to push and pull the crosslide. It has some flange or flat on the inside and then the whole dial and hand crank assembly on the outside is held with a nut on the end. Two nuts. One to adjust the fit, followed by the locknut. If there's no room for a locknut, a nylock nut or a little shakeproof Loctite would be appropriate.

As to why it wasn't a problem before? Maybe gunk as you suggested or there wasn't enough fit and friction between the stationary and moving parts to provide the grip to tighten up. If there isn't already, someone should write a book on "Why Stuff Happens".

I like the 222 threadlocker liquid, even though it's recommended for 1/4" or smaller.
1.) Make suitable assembly/fit.
2.) Toothbrush-scrub some alcohol on the nut/side away from the bearing.
3.) Apply mild heat (so I can still comfortably touch the assy.).
4.) Hold absorbent, dry tissue under the nut and drip the 222 on top of outer thread/nut interface side away from the bearing.
5.) Leave it set for suitable cure time or apply mild heat (so I can still comfortably touch the assy.).

There's virtually no chance of capillary action into the bearing if you only clean the outer interface and leave your lube inside the nut/shaft assy. It makes a nice (service removable) Ny-Lock substitute.

TGTool said:

Without seeing a parts diagram I'm just guessing, but if the nut on the end of the leadscrew is adjusted to take up the backlash between the screw and the taper attachment, I would expect to see a locknut to hold that position. That's the arrangement for the simpler situation with no taper attachment. The leadscrew is anchored at the apron on order to push and pull the crosslide. It has some flange or flat on the inside and then the whole dial and hand crank assembly on the outside is held with a nut on the end. Two nuts. One to adjust the fit, followed by the locknut. If there's no room for a locknut, a nylock nut or a little shakeproof Loctite would be appropriate.

As to why it wasn't a problem before? Maybe gunk as you suggested or there wasn't enough fit and friction between the stationary and moving parts to provide the grip to tighten up. If there isn't already, someone should write a book on "Why Stuff Happens".

Click to expand...

Yes, as you describe, there is a bronze bushing inside the apron, around the CS screw, which holds against the apron. The nut on the back of the CS screw needs to be snug enough to limit backlash but not so snug that it self tightens and locks everything up. Weirdest thing, I took the nut and washer off to inspect it. Noticed wear patterns were different, so I flipped it. Seems to have completely fixed everything, which is nearly as frustrating as having it constantly tighten down ha. Time will tell if that's only temporary. Also possible the smallest burr could have been causing it to grab. Appreciate the answers.

MaCon said:

I like the 222 threadlocker liquid, even though it's recommended for 1/4" or smaller.
1.) Make suitable assembly/fit.
2.) Toothbrush-scrub some alcohol on the nut/side away from the bearing.
3.) Apply mild heat (so I can still comfortably touch the assy.).
4.) Hold absorbent, dry tissue under the nut and drip the 222 on top of outer thread/nut interface side away from the bearing.
5.) Leave it set for suitable cure time or apply mild heat (so I can still comfortably touch the assy.).

There's virtually no chance of capillary action into the bearing if you only clean the outer interface and leave your lube inside the nut/shaft assy. It makes a nice (service removable) Ny-Lock substitute.

Click to expand...

Thanks, I may try this also.