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Battery and torque in a hand drill

  1. Oct 27, 2015 #1
    Hey, I have a project where my group needs to design a drill. I am wondering if anyone here knows how to calculate the torque we get from 3 AA-batteries on 3.6 V (10.6 V together). How does it work? It just needs to assemble furniture, so we don't need very much force on it. Do you know what type of motor (voltage of it) and which batteries work best?

    Thank you in advance.
  2. jcsd
  3. Oct 27, 2015 #2


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    Staff: Mentor

    These are all the things you'll need to show your teachers how you figured them out - the design process is a lot of what the grade is typically based on!

    So you should start by calculating the torque you need, picking an rpm you want, then look at catalogues of motors.
  4. Oct 27, 2015 #3


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    I would take the approach Russ suggests. Perhaps borrow a torque wrench and try measuring the torque required to tighten/loosen some screws.

    You mention 3.6V AA cells so we're probably talking about lithium cells of some sort. Some of these can generate very high currents - more then you may need and more than is safe. I recommend installing a fuse to limit the current while experimenting. Data on the cells should/may give you a value for the fuse.
  5. Oct 27, 2015 #4


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    As a lazy alternative to experimentation, torque & RPM specs for electric screwdriver can be found online.
    A certain Nordic company that happens to be the worlds largest kit-set furniture manufacturer happens to sell them, I'm sure their specs are appropriate :wink:.
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