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  • Make A Lead Screw By Hand?

    Hello, new member here. I am just getting into metalworking trades as a hobby and preparing to undergo training to become a machinist at community college. I have a great interest in the history of technology and as such, the history of industry. I have David Gingery's ""Build Your Own Metalworking Shop From Scrap" and am acquiring books as I can on patternmaking and so forth. I hope to at some point in the future build the Gingery machine shop.

    One thing I was reading though was about how a critical innovation in allowing the Industrial Revolution to really ramp up was the invention by Henry Maudslay of the screw-cutting lathe. I read that the principle innovations were the slide-rest, lead screw, and set of change gears and how Maudslay combined them together. The thing is, before inventing the screw-cutting lathe, Maudslay had to make his lead screw by hand.

    Well as a project, I would like to someday make a version of the Maudslay lathe from scratch, including hand-cutting the lead screw. What am I wondering is how would I go about learning how to do this? Are there any books or anything? I have Googled the subject on how to make a lead screw but it's always using machine tools to do so, not by hand (because who in their right mind in modern times would want to cut screws by hand? ).

    Any suggestions appreciated.

  • #2
    I read somewhere and I don't remember where, that he laid out a short section, a few inches, then chiseled it out and filed to finish. He then used this to cut other sections (using a follower on the short section) until he had a long leadscrew. After that he used that leadscrew to cut other better leadscrew's and repeat and repeat until he had one that he considered good enough. It is important to remember that in those days machining generally meant hammer and chisel, some kind of metal cutting hand saw and files so they got pretty good at doing those things. Lost skills for most today. Taps and dies didn't exist then, threads where either filed to shape or hand chased on some kind of rudimentary lathe IE: pole or treadle lathes.

    Good times.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

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    • #3
      in one of the machinist bed side reader books. he tells of a guy cutting threads on a lathe that had no lead screw.

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      • #4
        Theoretically at least - and probably realistically too - given that "feed rates" are just a set progression of the saddle per turn of the head-stock spindle that if the right gear-train could be set that a lead-screw or any thread could be cut if the lead of the "feed" (via the rack on the lathe itself and the pinion on the saddle) all that would then be needed would be to engage the longitudinal feed.

        You would have to keep it engaged throughout and just reverse the lathe to start again - no threading dial either - just as you would (have to) if cutting metric threads on an imperial/inch lead-screw or even if cutting metric thread on a metric lathe.

        So, if that worked then a lead-screw could be cut on a lathe without using the lathe lead-screw.

        "Feed rate" cutting is really just a variation of lead-screw thread-cutting after all.

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        • #5
          A guide for making the first pass at at leadscrew can be made by winding heavy wire on a cylinder and arranging a follower to track the valley between the adjacent wire turns.
          Regards, Marv

          Home Shop Freeware - Tools for People Who Build Things
          http://www.myvirtualnetwork.com/mklotz

          Location: LA, CA, USA

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          • #6
            Go to Amazon and but this book. I am a Journeyman and reference it all the time. " Shop-Theory-Henry-Trade-School Book " plus follow and learn from Tom on You Tube, he is GREAT machinist. Rich https://www.youtube.com/user/Figbash3

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            • #7
              By the time Maudslay was building his first screw cutting lathes, woodworkers had long ago adopted the wooden screw into clamps and vices. They were cutting threads with screwboxes. Blacksmiths too had thread cutting dies, but they couldn't cut a long straight on a bar. Roy Underhill shows a technique for making the big wooden nuts. He laid a spiral wrap of paper around the cylinder and sawed a kerf along the spiral. A piece of metal in the kerf caused the "screw" to move forward. The end of what I just called a screw was inlet with an adjustable cutter that cut the big threads in the matching nut as it wound thru.

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              • #8
                Originally posted by mklotz View Post
                A guide for making the first pass at at leadscrew can be made by winding heavy wire on a cylinder and arranging a follower to track the valley between the adjacent wire turns.
                Two strips of suitable width wound together over a bar, then remove one strip. (Or prebend one as as a follower) I could see doing it with solder on the remaining one and winding them hot.

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                • #9
                  According to what I have read the original lead screws were cut by hand with a chaser, looks like a piece of a screw machine die head, it has a thread, with the helix angle, the technique required to hand chase does require practice, the thread was "struck" into the rotating bar with the heel of the chaser, steady pressure on the chaser cases it to pull itself along, I have tried it and it does work quite well, apparently maudslay used this technique.
                  Mark

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                  • #10
                    Thanks for the information thus far.

                    Originally posted by bob308 View Post
                    in one of the machinist bed side reader books. he tells of a guy cutting threads on a lathe that had no lead screw.
                    I'd love to get those books, problem is they each cost an arm and a leg right now. From what I had read, the author went through a nasty divorce and his ex-wife is entitled to profits from the books or something and thus he stopped printing them.

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                    • #12
                      Originally posted by Richard King View Post
                      Go to Amazon and but this book. I am a Journeyman and reference it all the time. " Shop-Theory-Henry-Trade-School Book " plus follow and learn from Tom on You Tube, he is GREAT machinist. Rich https://www.youtube.com/user/Figbash3
                      Thanks for the suggestion, looks like a very cool book and Youtube source

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                      • #13
                        If you already have the lathe but need a leadscrew for it to cut threads I would think it would be a very easy task to "free hand" a decent length of threads eventually that could be copied over and over again into a long screw like mentioned good enough to cut a better screw and so on and so forth.
                        Andy

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                        • #14
                          That "copying over and over" rather suggests a pretty good (almost) "metrology" set-up as the measuring set-up would need to be very good indeed.

                          It may be easier if a horizontal universal mill and universal dividing head were used - with a good vertical milling attachment.

                          http://www.lathes.co.uk/victoria/img9.gif

                          http://www.lathes.co.uk/victoria/
                          Last edited by oldtiffie; 02-23-2015, 10:17 PM.

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                          • #15
                            It should be possible to cut a decent screw on a lathe using sprockets and a chain to move the carriage at a uniform rate proportional to the spindle rotation. I have seen pictures of some machines using chain drive on a carriage.
                            Don Young

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