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  • Threading problem on 9X 20 lathee

    I can no longer engage the threading lever on my My Jet lathe. Any suggestions? Thanks, Bob.
    Last edited by Bob Fisher; 10-05-2016, 07:18 PM.

  • #2
    Not at all?

    Even turning by hand and trying at all positions?

    That sounds more like a mechanical issue with the mechanism, something jamming it, possibly chips stuck in the half nuts, or elsewhere in the works. Or possibly something loosened up.

    Does the handle stop short?

    Or does the handle move OK, but the nuts do not engage?
    CNC machines only go through the motions

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    • #3
      Does this lathe have power long or cross feeds? If so, are they engaged?

      allan

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      • #4
        Take a chain that's about 10 feet, then a nylon rope that's long enough for your anchoring needs and use the lathe for what it excels at, a boat anchor

        Comment


        • #5
          Might I suggest you stuff it in your ear, RB? Some people can neither afford, nor have the room for, the classic "big American Iron"- and may not need it anyway, given the size of parts they might be making.

          Personally, I used a typical, unmodified Grizzly 9x19 for around 3 years, because I had work to produce, and I was tired of waiting around for what YOU might consider a "good" lathe to appear- in this case, meaning a worn-out, 50-year-old American brand that probably doesn't even have a quickchange box.

          In that three years, that machine probably made me $50K. I then sold it for almost what I paid for it, since it was still in damn-near-new condition.

          So, y'know, I'd like to reiterate piss off, in the kindest way possible.

          Doc.
          Doc's Machine. (Probably not what you expect.)

          Comment


          • #6
            There is a lever for the half nuts on the apron, and there is another on the quick change gearbox. Which is it?

            There is also a lever for fine feed on the apron, and if that is engaged it locks out the lever for the halfnuts.


            Dan
            At the end of the project, there is a profound difference between spare parts and left over parts.

            Location: SF East Bay.

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            • #7
              Thanks Doc
              George from Conyers Ga.
              Remember
              The early bird gets the worm, BUT it's the second mouse that gets the cheese.

              Comment


              • #8
                Originally posted by kitno455 View Post
                Does this lathe have power long or cross feeds? If so, are they engaged?

                allan
                I can just about guarantee that machine has no lockout, if that is the issue. It does have a turning feed, I don't think it has crossfeed.

                http://www.micro-machine-shop.com/Je...the_manual.pdf
                CNC machines only go through the motions

                Comment


                • #9
                  Have a look at the locking cam and it's ball detent,those are the two pieces closest to the problem.At least with the 9x20 the carriage and apron are no big deal to take apart and put back together.
                  I just need one more tool,just one!

                  Comment


                  • #10
                    Originally posted by J Tiers View Post
                    I can just about guarantee that machine has no lockout, if that is the issue. It does have a turning feed, I don't think it has crossfeed.

                    http://www.micro-machine-shop.com/Je...the_manual.pdf
                    If it's the same machine as the HF (as many have asserted many times) there is an interlock so you can use the longitudinal feed or the halfnuts but not both.

                    Dan
                    At the end of the project, there is a profound difference between spare parts and left over parts.

                    Location: SF East Bay.

                    Comment


                    • #11
                      Originally posted by danlb View Post
                      If it's the same machine as the HF (as many have asserted many times) there is an interlock so you can use the longitudinal feed or the halfnuts but not both.

                      Dan
                      Well, have a look at the linked manual, and find the interlock. The BD920 is the usual "Jet" model. I didn't see an interlock, bit there could be one that is not so obvious.
                      CNC machines only go through the motions

                      Comment


                      • #12
                        Originally posted by J Tiers View Post
                        Well, have a look at the linked manual, and find the interlock. The BD920 is the usual "Jet" model. I didn't see an interlock, bit there could be one that is not so obvious.
                        It would make sense to have an interlock, otherwise the engagement of both at the same time would break something quickly. I've forgotten, have you actually owned the model under discussion?

                        It will take Bob (the OP) seconds to confirm whether that's the problem. It will take you half an hour to search the manual parts list. I'll leave searching the manual to you. I was able to verify that my model (HF) has one, and a cursory look at the parts section of the manual you posted appears to match what's in my manual.


                        Dan
                        At the end of the project, there is a profound difference between spare parts and left over parts.

                        Location: SF East Bay.

                        Comment


                        • #13
                          Originally posted by danlb View Post
                          It would make sense to have an interlock, otherwise the engagement of both at the same time would break something quickly. I've forgotten, have you actually owned the model under discussion?

                          It will take Bob (the OP) seconds to confirm whether that's the problem. It will take you half an hour to search the manual parts list. I'll leave searching the manual to you. I was able to verify that my model (HF) has one, and a cursory look at the parts section of the manual you posted appears to match what's in my manual.


                          Dan
                          I have messed around with one, never bought one. For one thing, the experience was not a nice one, and for another the Logan was cheaper and larger.

                          I looked at the manual and parts breakdown before I posted the link. 5 or 10 minutes only, including the search. The only thing that might be an interlock is the "joint plate", item 49. I cannot see what it does other than potentially being an interlock, despite its name. It could slip into a groove in the feed sliding gear shaft.

                          If that IS an interlock, it may be jammed, or jamming the half nuts, or the turning feed may be not fully out of mesh. Or there could just be a fault with the half nut mechanism itself.
                          CNC machines only go through the motions

                          Comment


                          • #14
                            Originally posted by Doc Nickel View Post
                            Might I suggest you stuff it in your ear, RB? Some people can neither afford, nor have the room for, the classic "big American Iron"- and may not need it anyway, given the size of parts they might be making.

                            Personally, I used a typical, unmodified Grizzly 9x19 for around 3 years, because I had work to produce, and I was tired of waiting around for what YOU might consider a "good" lathe to appear- in this case, meaning a worn-out, 50-year-old American brand that probably doesn't even have a quickchange box.

                            In that three years, that machine probably made me $50K. I then sold it for almost what I paid for it, since it was still in damn-near-new condition.

                            So, y'know, I'd like to reiterate piss off, in the kindest way possible.

                            Doc.
                            Well it's water under the bridge... My point is that theres better lathes that cost less than can be bought brand new, IE... The 8x12/14 lathes by HF and Lathemaster. I have an 8x14 from LatheMaster, and my SB 9c is nothing special to write home about... I would like to get a bigger lathe, preferably CNC.
                            I used to own an Enco 9x20 lathe, I do not remember it having a powered cross feed.

                            Comment


                            • #15
                              I have a Harbor Freight 9x20, circa 2003, and I verified that it does have an interlock that prevents simultaneous engagement of the screw-cutting half-nut and the power longitudinal feed. It does not have power cross-feed. I'm pretty happy with the lathe and I like it better than the Clausing 12" I used in my machine shop class.
                              http://pauleschoen.com/pix/PM08_P76_P54.png
                              Paul , P S Technology, Inc. and MrTibbs
                              USA Maryland 21030

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