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John Stevenson's gear cutting writeup

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  • #16
    As for the bass shafts or tubes, I bought mine years ago at a Hobby Shop. They fit together very well. I did not check for steel ones but they might have them also.
    I have most of the blanks cut for the gears, now I just need to turn them to the proper diameter and spend the long tedious hours of cutting the teeth. A number of them are the same diameter so I will make a mandrel and turn and cut those at the same time.
    All this stuff I have for this project have been setting in a box for 7 or 8 years waiting for me to continue the job.
    Someone questioned the accuracy of the planets rotation and as I remember the Earth one was off the most.
    _____________________________________________

    I would rather have tools that I never use, than not have a tool I need.
    Oregon Coast

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    • #17
      Originally posted by CCWKenr View Post
      As for the bass shafts or tubes, I bought mine years ago at a Hobby Shop. They fit together very well. I did not check for steel ones but they might have them also.
      I have most of the blanks cut for the gears, now I just need to turn them to the proper diameter and spend the long tedious hours of cutting the teeth. A number of them are the same diameter so I will make a mandrel and turn and cut those at the same time.
      All this stuff I have for this project have been setting in a box for 7 or 8 years waiting for me to continue the job.
      Someone questioned the accuracy of the planets rotation and as I remember the Earth one was off the most.
      Great resources for sure Rich. Thanks for sharing.
      Last edited by Deanda; 11-01-2021, 01:09 PM.

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      • #18
        Does anyone else have trouble understanding John's technical writing? I learned back in grad school that if I read something a few times and still don't get it, to look for a different textbook because my author was having a bad day when he wrote the part I didn't get. The first time I didn't even understand what the buttons were for. What I don't quite get still is how are the pins attached to the form tool and how the pins are ground to give relief. Sure wish there were some clear photos, oh well.

        metalmagpie

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        • #19
          It is pretty much described in figure 2. The "pins" are "T" shaped, the top button the desired diameter, reduced in diameter on the lower part to fit in the holes in the tool holder which are on the appropriate centers. The pins are held by grub a screw from the side. The tool holder is fabricated with the 5* relief and pins or buttons ground flat on top.

          Probably the best place for the beginner to start is with the Ivan Law book, after that most of the hard part becomes understandable.
          Jim H.

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          • #20
            The pins are dropped into drilled holes. Button is then soldered or tack welded into place.
            tool holder is milled with a 5-7 degrees of negative top rake.
            That gives a 5-7 degrees of relief on the front of the tool for cutting.

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            • #21
              I found the Ivan Law book online in PDF. After reading it John's writing is MUCH clearer, thanks!
              Last edited by metalmagpie; 11-09-2017, 12:37 AM.

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              • #22
                Originally posted by metalmagpie View Post
                i found the ivan law book online in pdf. After reading it john's writing is much clearer, thanks!
                ditto

                cs

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