Motor shaft reducer?

Discussion in 'General' started by JustinScott, Jun 28, 2017.

  1. JustinScott

    JustinScott Well-Known Member

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    Hi everyone,

    The motor on my boat has a 4mm shaft on it. It is impossible to find 4mm 32p gears.

    I bought a 1/8" gear (3.125mm) with the intention of drilling it. Fortunately I tested drilling out another gear first because I wasn't successful.

    Next I tried to turn my motor shaft down to 3.125mm; but I couldn't find anything that would cut into that steel.

    So I'm at a loss, does anyone have any suggestions other than buy a new motor?
     
  2. Lou

    Lou It's just toy boats -->> C T D <<-- Admiral (Supporter)

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    Turn the motor on and use a piece of sandpaper on a stick to reduce the shaft diameter.
     
  3. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    Or go to 5mm gears. 4mm bullet connectors typically have 4mm id and 5mm od on the receptacle
     
  4. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    I've done what VVaholic suggested except I used a file. Make sure you cover all the holes in the casing as you don't want metal filing getting in there.
    [​IMG]
     
  5. SteveT44

    SteveT44 Well-Known Member

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    https://www.servocity.com/4mm-bore-32p-16t-shaft-mount-pinion-gear
     
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  6. JustinScott

    JustinScott Well-Known Member

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    VV/Beaver, I tried with a file too. It didn't seem to be making much progress. Can you tell me more about your technique? What kind of file did you use?

    Greg, I'm not sure I'm visualizing what you are saying. Can you send a link/photo?

    Steve, I'm not sure I want to use brass gears. Do you have experience with them?
     
  7. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

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    what I use is the receptacle from https://goo.gl/images/smkUMS . Put shaft inside, gear over outside, clamp down hard with setscrew. is soft enough to grab the shaft really quite well.

    I am using cheap HK steel gears with stainless screws. I just keep them well oiled, have not had any rust issues.
     
  8. SteveT44

    SteveT44 Well-Known Member

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    Brass is the typical material for motor pinion gears. That being said. I don't personally use gears in my drive trains. I prefer direct drive setups.
     
  9. Beaver

    Beaver 2020 Rookie of the Year Admiral (Supporter)

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    Most shafts are case hardened so it will be slow progress till you get through. It took me a little while to get through that hardened outer layer but then the rest was easy. I used a small triangle file, but that just happened to be what I had on hand.