Lead Screw Removal Jet GHB1340 lathe
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  1. #1
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    Default 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
    Last edited by gr71; 03-13-2019 at 04:39 PM.

  2. #2
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    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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    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.

  4. #4
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    Quote Originally Posted by neanderthal mach View Post
    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.
    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 ask555.jpg44.jpg

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    Did I have the wrong model Jr?

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    Quote Originally Posted by partsproduction View Post
    Did I have the wrong model Jr?
    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

  7. #7
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    Quote Originally Posted by neanderthal mach View Post
    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.
    I have done it that way before but a slide hammer is easier.

    Regards Tyrone.

  8. #8
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    Quote Originally Posted by Tyrone Shoelaces View Post
    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.
    .
    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.


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