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Cordless drill motor

Discussion in 'Robotics & Mechatronics' started by Electronics4you, Jul 28, 2014.

  1. Electronics4you

    Electronics4you Member

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    Hi there,

    I want to use 4 cordless drill motors to power a mobile robot, but I need some assistance determining the thread size of the motor axis. The motor is from a B&D cordless drill and when the chuck is removed, a thread is revealed. This is almost a standard thread on all cordless drills, but I can't figure out the size/type of it in order to buy a corresponding nut.

    Approximate dimensions are
    - Outer diameter: 12.5 mm (0.492 in)
    - Pitch: 1.3 mm (0.051 in)

    I guess the dimensions correspond to an American standard. Anyone with special knowledge on cordless drills?
     
  2. Pommie

    Pommie Well-Known Member Most Helpful Member

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    That sounds like it's a 1/2 inch, 20 TPI thread. TPI = teeth per inch. It could be Unified Fine (UNF). See this page for other possibilities.

    Edit, you may have more luck getting British cycle threaded nuts from a bicycle shop.

    Mike.
     
    Last edited: Jul 28, 2014
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  3. Electronics4you

    Electronics4you Member

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    Seems like a good match - at least based on the UNF. I think the next step is to purchase a UNF nut to check the fit.

    Thanks Mike
     
  4. dave

    Dave New Member

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  5. Electronics4you

    Electronics4you Member

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    The British cycle thread does not seem to be available with 1/2" and 20 TPI - none of the BSC charts contain it.
     
  6. Pommie

    Pommie Well-Known Member Most Helpful Member

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    If you look half way down the link I posted 1/2 inch BSCycle is available in 20 and 26 tpi.

    Mike.
     
  7. Electronics4you

    Electronics4you Member

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    Ok, did not look for it there, but went straight to Google :)
    Strange how other tables only show the 26 TPI and not 20 TPI like your table shows.

    I'll stick to the UNF, due to the availability in my country.

    Thanks again
     
  8. Pommie

    Pommie Well-Known Member Most Helpful Member

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    If you can easily get UNF then go for that. I think getting UNF here in Australia would be nigh on impossible hence my bicycle suggestion. BTW, bicycle pedals appear to be 1/2 inch 20 tpi.

    Mike.
     
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  9. KeepItSimpleStupid

    KeepItSimpleStupid Well-Known Member Most Helpful Member

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    Last edited: Jul 28, 2014
  10. Electronics4you

    Electronics4you Member

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    KeepItSimpleStupid: I have only used a slide gauge as I don't own a pitch gauge myself (unfortunately), but it doesn't look like a 1/2-24 (UNF)
     

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