Cross feed screw jammed

[Fixnair]

I've been gone for a couple of years but I'm back now and need some advice from you experts. I packed up my shop and residence a couple of years ago and moved the whole kit & kaboodle from California to Sapulpa OK. I'm just now getting my shop put together and ran into a problem with my South Bend 13 X 20 lathe.

My cross feed screw jammed on me. So I took it apart yo figure out why. I found the lead screw was fastened to the adjustment spindle by a straight pin. The pin had worked its way out and prevented the spindle from turning. Probably caused by the four day 2000 mile trip to Oklahoma.

The disassembly was pretty straightforward 'till I removed the lead screw from the spindle. Out fell several pieces of lead slugs (as in plumbers lead). Let's not get confused between lead (leed) and lead (led).

What the heck are these for? Got me scratching my head. I'm thinking that the hole in the spindle is about 1-/2" deep and the lead screw is only inserted maybe 1/2" into the hole and he lead slugs were put there to push on the lead screw and relieve the tension on the connecting pin.

This pin arrangement seems to be a pretty sloppy fit. Is this to allow the lead screw to self align with the nut? My plans were to use a tapered pin in its place but maybe that wouldn't work.

I'm going to try & attach a picture to this.

Thanks for any input you may have.

 

[10K Pete]

I'm no expert on that model SB, but that looks a lot like a screw set up for use with a taper attachment. What they call a telescoping lead screw. Except yours seems to be missing the straight, unthreaded, part at the far end that attaches to the taper attachment. Hmmmmm...... Also, the end that goes into the crank end would have an unthreaded part with a key.....
Maybe someone mixed some parts.....?????

Pete

 

[ruzzie]

Here is a link to a South Bend manual, looking at page 40 of the manual it shows the two different types of setups.
Going by you picture it looks to me like a modified taper turning shaft.

http://neme-s.org/Shaper%20Books/South%20Bend/CE3458%20Parts%20Manual.pdf

Paul

 

[Fixnair]

Thanks for the reply Pete and ruzzie. I think you are right Pete. It probably had a taper attachment on it. The lead screw had something on the end but was hack sawed off. Whoever did it got lazy and stopped sawing about 1/8" from completion and then they broke it off to complete the cut. The crank end of the lead screw had been slotted for a 1/4" key.

I got it repaired by removing the lead slugs and shoving the lead screw all the way into the crank spindle. Wrapping a .005" shim around the lead screw to reduce the sloppy fit. I also ground a flat on the lead screw opposite the key slot then tapped 1/4-28 threads in the hole where the pin went and used two set screws to fix the lead screw.

By shortening the effective length of the lead screw I reduced the amount of inward travel of the cross feed but, as is, it goes about 1" past center. Good enough for me. I don't think I will ever have to make a cut on the backside of a part. If you guys see a problem with my fix please let me know

I also appreciate the link to the book ruzzie. I downloaded it and filed it with the rest of the tech pubs I have in file.

Thanks again to you both for responding.