Lead Screw Removal Jet GHB1340 lathe

Jet GHB1340 lathe mid-90's
I am just a hobby machinist so take it easy on me.
I'm trying to remove the lead screw so I can remove the apron. The power feed rod came out really easy after removing the shear pin. The lead screw is a very hard press fit. I don't think it should be. I put minimum heat and sprayed some WD40 and all I could do was just barely get it to turn with a pair of Channel Locks against the gear train, which I was not very comfortable doing for fear of damaging gears. I could only get it to move out a 1/2 mm turning and pulling at the same time, which is very hard to do. I don't know how to get enough force to extract it. I am hesitant to give it any real heat for fear of the nearby paint and gearbox.

It's so hard to turn, it doesn't even need a shear pin. It would probably still tear up the halfnut if you crashed it with the pin out.

Any suggestions?

My second question is about the alignment taper pins. There are two alignment taper pins connecting the saddle and apron. They are threaded on top for 5mm bolts, but what is the best way to extract them? I tried to lever a pair of pliers on a bolt threaded in the top, but it just started bending the bolt.

There are two in the feed rod/ lead screw support on the tailstock end of the lathe. They don't have any threading. How in hades do you get those out?

Thanks

In before the thread lock.

If those taper pins are threaded in the big end then that's meant as the extraction method. Use a heavy wall hollow spacer above each pin with a heavy washer on top. Run the bolt in and tighten. That pulls the pins out. Obviously the spacer length and bolt length are important since bottoming out the bolt in the threads before it starts pulling the pins is pointless.

Jet Metal Working Lathe | GHB-1340A | eReplacementParts.com

Looks like a simple taper pin if I have the right model, this is a GBH1340A parts dwg.

neanderthal mach said:

In before the thread lock.

If those taper pins are threaded in the big end then that's meant as the extraction method. Use a heavy wall hollow spacer above each pin with a heavy washer on top. Run the bolt in and tighten. That pulls the pins out. Obviously the spacer length and bolt length are important since bottoming out the bolt in the threads before it starts pulling the pins is pointless.

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Been determined before,,the bigger Jet's are ok to talk about
here's a couple images from the owners manual,if you want/need more just ask

Did I have the wrong model Jr?

partsproduction said:

Did I have the wrong model Jr?

Click to expand...

maybe it is me,,,My reference was to GH-1340W/1440 W

close but I am thinking it came a couple years later,,my bad

neanderthal mach said:

In before the thread lock.

If those taper pins are threaded in the big end then that's meant as the extraction method. Use a heavy wall hollow spacer above each pin with a heavy washer on top. Run the bolt in and tighten. That pulls the pins out. Obviously the spacer length and bolt length are important since bottoming out the bolt in the threads before it starts pulling the pins is pointless.

Click to expand...

I have done it that way before but a slide hammer is easier.

Regards Tyrone.

Tyrone Shoelaces said:

I have done it that way before but a slide hammer is easier.
Same with really tight lead screws or feed shafts. Drill and tap them up the end and use the slide hammer.
.

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You can't beat having a slide hammer for these jobs. I have removed tight leads crews before but engaging the half nuts and then rocking the screw out CAREFULLY but using the long travel hand wheel.

I seem to have quoted myself in the above post. That " Stella " must be stronger than I thought !

Regards Tyrone.

I thought I should come back and update this post for future viewers with the same problem.

I managed to get the lead screw out.

1. I put the quick change gear box in the finest pitch setting.
2. Engaged the half nut.
3. Heated the shaft where the lead screw is connected with a propane torch
4. Took the spindle out of gear and turned it by hand until I felt the tension while holding the half nut down to keep it from popping out of engagement.
5. I tapped on the connection with a hammer and the lead screw gradually came out.
6. I had to gradually add tension by turning the spindle and tapping with the hammer.

Once it was out I relieved the inside of the shaft with some emery paper so it would not be so hard.

Once the lead screw was out it was easy to drop the apron and Knock the taper pins in it back out from underneath.