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  1. #1
    Join Date
    May 2005
    Posts
    9

    Question units per inch math

    hi what is the formula for computing steps per inch
    for example 360/.9 degree half step=400 steps per turn.
    so 400*20tpi lead screw=8000 steps per inch.* 30:1 gear reduction
    ie 8000*30 =240000 steps will give me 1 inch.
    is my math correct or did my brain fart?

  2. #2
    Join Date
    Aug 2003
    Posts
    73
    Yes your math is correct... Are you sure its 30:1 and not 3:1 ???

    I think 30:1 will be a big problem for you.

    That would give you a resolution of .000004 wich is way to much.. would also really limit the speed of your unit..

  3. #3
    Join Date
    Oct 2004
    Posts
    590
    (steps/rev)*(rev's/rev)*(rev's/inch)=steps/inch

  4. #4
    Join Date
    Aug 2004
    Posts
    2849
    Quote Originally Posted by OCNC
    (steps/rev)*(rev's/rev)*(rev's/inch)=steps/inch
    Hmmm...that gives me step *rev's squared/inch rev squared

  5. #5
    Join Date
    Oct 2004
    Posts
    590
    Quote Originally Posted by ViperTX
    Hmmm...that gives me step *rev's squared/inch rev squared
    [(step)*(rev^2)]/[(inch)*(rev^2)]

    The (rev^2) cancel and the units remaining are step/inch where inches are the linerar inches of travel.

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