Shaft Diameter

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  • evildave42
    Lieutenant, Junior Grade
    • Nov 2012
    • 14

    Shaft Diameter

    Hi yall,
    I have several motors with 2.3mm shafts on them, I want to attach them to prop shaft connectors (the ones that use "dogbones") but these connectors fit a 1/8 inch shaft.
    I tried to press a 1/8 inch brass tube onto the shaft as I saw Dumas motors came with, but the only tubes I can find have an internal diameter that is slightly too big and it just slides on.

    How do you guys connect these smaller shaft motors to the larger shafts?
  • He Who Shall Not Be Named
    Moderator
    • Aug 2008
    • 12255

    #2
    Yall?! Who are you .... Foghorn Leghorn? http://www.youtube.com/watch?v=avx1UcXalqo

    Solder a piece of 1/8" brass rod into the bore of that Dumas universal coupler; mount the coupler in the chuck of a lathe (or drill) and bore out the rod with a drill bit just a tad larger than 2.3mm; drill out the set-screw (grub-screw for you Brit's) hole and re-thread. Wa-la! ... Victory.

    David
    Who is John Galt?

    Comment

    • Kazzer
      *********
      • Aug 2008
      • 2848

      #3
      Originally posted by evildave42
      Hi yall,
      I have several motors with 2.3mm shafts on them, I want to attach them to prop shaft connectors (the ones that use "dogbones") but these connectors fit a 1/8 inch shaft.
      I tried to press a 1/8 inch brass tube onto the shaft as I saw Dumas motors came with, but the only tubes I can find have an internal diameter that is slightly too big and it just slides on.

      How do you guys connect these smaller shaft motors to the larger shafts?
      First of all, lets convert the dimensions to a level playing field.

      2.3mm = .09" or almost 3/32" (3/32 = .0938mm) 1/8" = .125" = 3.175mm a difference of .875mm

      So we need a tube with an ID of 2.3mm and OD of 3.175mm
      or ID of 3/32" and OD 1/8"

      I wonder if one of those mini pipe cutters wouldn't nip a groove in the tube if it were run over the tube as it sits over the 2.3mm shaft, just to take up that .0038mm? Actually, I would have thought some Loctite would have done that.

      Or if you have a lathe, just take some 1/8" brass rod and drill a 2.3mm hole down through it.

      And then, I've seen HWSNBN using some plastic pipe and warming one end to stretch it over the larger shaft.
      Stop messing about - just get a Sub-driver!

      Comment

      • Subculture
        Admiral
        • Feb 2009
        • 2119

        #4
        If you have lathe, or access to one, I would get some brass stock slightly larger than 1/8" and turn it down to size, then drill out for the shaft size and part off. If you stick 1/8" stock straight in the chuck and drill that out, the shaft will almost certainly run eccentric- as chucks never run exactly true. Now the coupling will take that up, but you will end up with more vibration in the drive shaft than is desirable.

        For very accurate work, collets or a four jaw chuck are pressed into service. The latter requires setting up with a clock.

        Comment

        • He Who Shall Not Be Named
          Moderator
          • Aug 2008
          • 12255

          #5
          (clock = dial-indicator)
          Who is John Galt?

          Comment

          • evildave42
            Lieutenant, Junior Grade
            • Nov 2012
            • 14

            #6
            I don’t really have any metal working tools. I can cut and drill some brass, but I don’t have the equipment to be very accurate. Is there no quick fix or anyone who manufactures an adaptor or coupling the correct size?

            Comment

            • He Who Shall Not Be Named
              Moderator
              • Aug 2008
              • 12255

              #7
              ... then, you're in the wrong game. Come back when you have the proper tools and know how to use them.

              Or would you attempt a moon trip with a sky-rocket jammed up your butt, and pillows taped to your forehead to cushion the landing?!

              Or, you can hire a Machinist to do the work for you (that's what you do when you buy an SD, by the way).

              David
              Who is John Galt?

              Comment

              • Kazzer
                *********
                • Aug 2008
                • 2848

                #8
                Originally posted by He Who Shall Not Be Named
                ... then, you're in the wrong game. Come back when you have the proper tools and know how to use them.

                Or would you attempt a moon trip with a sky-rocket jammed up your butt, and pillows taped to your forehead to cushion the landing?!

                Or, you can hire a Machinist to do the work for you (that's what you do when you buy an SD, by the way).

                David
                I've tried folks! I really have. It's been a complete waste of time. Years of editing, cajoling, asking nicely, threatening, making Rose lock him in his cave. I've even bribed Ellie to inflict pain. I've tried everything to get him to be nice to our customers, and just as I think I'm getting somewhere, the little gremlin in his feeble brain kicks in and we get another out-burst like this one today.

                It is no wonder his parents kicked him out, and although I don't think The Navy actually went that far, I'm sure they would have liked to. Instead, he was put on latrine duty, and especially the pigeon poop removal from the top of his submarine's sail. That's why you'll see such intricate detail of how pigeon poop slithers down a surface depicted on all his models. He's an expert pigeon poop painter, (and scraper). At least they knew where he was when everyone else was on shore leave. Either the latrines or on deck, bucket, mop and scraper in hand.

                There's got to be something wrong with him. Was he put in a dark cupboard under the stairs as a child? Or made to eat carbolic soap?

                Could we perhaps get someone to drill one of those special holes in his noddle, so we could poke a little wire in there and wiggle it a bit, and see if we can find the short?

                I'm struggling for help here folks, so if you have any ideas, please let me know.

                It's very sad, very sad.
                Stop messing about - just get a Sub-driver!

                Comment

                • Kazzer
                  *********
                  • Aug 2008
                  • 2848

                  #9
                  Try one of these http://www.tools-plus.com/empire-lev...m_term=ELM2812

                  Only $3.00

                  I think you'll find that when you cut through the tube, the end will be knurled in a bit. Run another cut about 1/4" from the end, but don't cut through, this should make the inside dimension smaller.
                  Stop messing about - just get a Sub-driver!

                  Comment

                  • evildave42
                    Lieutenant, Junior Grade
                    • Nov 2012
                    • 14

                    #10
                    Originally posted by Kazzer
                    Try one of these http://www.tools-plus.com/empire-lev...m_term=ELM2812

                    Only $3.00

                    I think you'll find that when you cut through the tube, the end will be knurled in a bit. Run another cut about 1/4" from the end, but don't cut through, this should make the inside dimension smaller.

                    Oh, thats is a neat tool! Multiple uses. I think I'll get one of those, thanks.

                    And as for being "in the wrong game", most of my subs are low budget. My first sub was an 18 inch model conversion of a Type VII, my best performing sub so far. And I did it all for about $60. So it can be done, for my 4th sub, gonna build another one with all that I have learned since (even wondering if I could cram a SNORT in it or maybe a piston system based around a syringe or something).
                    The 38 inch scratch-built sub I'm working on right now shouldn't require all those tools (except for perhapse the motor coupling) and should cost me about $200 all said and done. Come to think of it, by far the most expensive/complex sub I have is the Revell Type VII conversion kit I purchased from D&E.

                    Kazzer, thank you for being understanding, especialy here in the "Silly Questions from NEWBIES" forum.

                    Comment

                    • trout
                      Admiral
                      • Jul 2011
                      • 3545

                      #11
                      Evildave42, if I was to guess, David wants to see what you are made of. You have had 5 posts here, he does not know what you can or can't do. I got my first kick in the pants after my first or second post. If you have read through some of the posts, you will see that if you show yourself as someone who shares your experience and can take correction, he does open up and will support you to completion. He has a huge heart, but if you tell him I said that, I will hunt you down.
                      If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                      Comment

                      • evildave42
                        Lieutenant, Junior Grade
                        • Nov 2012
                        • 14

                        #12
                        Well, that might be true.
                        But if I scared off that easially I never would have finished my Dumas Bluefish. (Not gonna buy one of their subs again)

                        I've got several posts on RCgroups, I didn't even know this one existed until I was asking about the Snort system and someone there mentioned it.

                        Comment

                        • trout
                          Admiral
                          • Jul 2011
                          • 3545

                          #13
                          Then your the stuff that will work well here! This is like testosterone central. You can not be too sensitive or too timid. You must pull your weight and share. There is a lot of grunting, scratching, and swearing. Good times!

                          "But if I scared off that easially I never would have finished my Dumas Bluefish." I like you already, welcome aboard!
                          If you can cut, drill, saw, hit things and swear a lot, you're well on the way to building a working model sub.

                          Comment

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