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  1. #1
    Join Date
    02-13-2013
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    Steps Per Inch - How Far Is That Really?

    This is probably a stupid question, but how much in distance is a step? I guess it depends on lots of factors like thread count, ipm... but what would the approximate/average/eyeball difference travel be for 100 steps? Just wondering.

    I trued up my 3040 machine this evening in Mach. I noticed on some very small gears today that they were not perfectly circular. When I checked Mach and did the re-calibration I noticed that there was a difference between the x and y of about 191.697... It's all trued up now, both the x and y have the same number and when I run tests at different lengths it is a beautiful thing - spot on!

    I'm curious to see how nice and circular gears will be now.


    Dan
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  2. #2
    Join Date
    05-31-2010
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    Re: Steps Per Inch - How Far Is That Really?

    There's really no "rough" guess - it depends on whether you have micro-stepping enabled (or not) and what kind of lead your screws/rack/belts run at and if there's any gearing up or down between the stepper and the drive system.

    There's no "100 steps would be x inches" because if you have 2x microstepping, it'd be half that - i have 8x microstepping, so it'd be 1/8 that. My X and Y screws have .500" lead, so a single 1/200 step (typical for steppers) would move about .0025" in theory. So 100 of those would put me at around a quarter inch. But with 8x microstepping, it's more like .03125" for my X and Y axis.

    It's very machine and electronics specific ... but for YOUR machine, about 100 steps is about the diametric difference in your oval-shaped circles.
    Jason Beam
    Sacramento, CA
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  3. #3
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    02-13-2013
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    Re: Steps Per Inch - How Far Is That Really?

    Cool. Thanks, Jason.

    Since all the parts on this machine are the same I think the circles now will be pretty good.

    Dan
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  4. #4

    Re: Steps Per Inch - How Far Is That Really?

    your ballscrew will make your life simple..
    if you can keep clean, you wont experience ever backlash..


    for inlaywork I make 0.05mm negative offset and that sufficient..
    a 100 mm circle I can measure 0.03-0.04mm deviancy.. and that is way better than wood need..


    if you have hss bit, then slow down rpm to 3000 and it keeps longer.. still not what a carbide takes..
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  5. #5
    Join Date
    02-13-2013
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    Re: Steps Per Inch - How Far Is That Really?

    Thanks Viktor.

    My spindle goes from 0 to 8000 - as a rough rule should I be in the 3000 to 4000 range for .5" plywood?

    Dan
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  6. #6

    Re: Steps Per Inch - How Far Is That Really?

    yes and no




    yes if it is hss , then keep low the rpm
    with carbide the spindle cant excess the rpm


    the rpm regardless of the plywood thickness.. for your machine and for this spindle I think you cant cut trough a 1/2 in plywood in one pass..


    that's why I tried to show you on other post the one flute tool


    a 12mm long flute could work for you.. and it is carbide..




    http://www.ebay.com/itm/10X-1-8-Carb...-/281330931666


    I using these and good for acrylic, wood..
    for aluminum, you need to ground beck to short the flute..


    this you can spin with the max rpm.. I think your spindle might takes about 1/8 depth ..
    the 300-400 watt output don't let you cut real deep..
    Last edited by cnclurker; 04-20-2015 at 1:56 am.
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  7. #7
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    02-13-2013
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    Re: Steps Per Inch - How Far Is That Really?

    Yes - I did see the link before for the end mills. I did order a similar set.

    Thanks,
    Dan
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  8. #8
    Join Date
    06-19-2010
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    Gods country -- New England
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    Re: Steps Per Inch - How Far Is That Really?

    If there is anything you want to "cheap out" with - cutters is not that thing.
    Art and Creativity - Collide with the Functionality of CNC - priceless
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  9. #9
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    02-13-2013
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    Re: Steps Per Inch - How Far Is That Really?

    I actually ordered two sets of cutters for some comparisons - the cheaper ones just to see, and then a better set with more sizes.

    As Jason noted...I'm searching for the right combo of speeds and feeds - trying to get my zen on.

    Dan
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  10. #10
    Join Date
    06-19-2010
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    Re: Steps Per Inch - How Far Is That Really?

    Speeds and feeds is not really all that complicated, and doesn't require zen.

    PM your email address and I will send the spreadsheet on RPM and Feedrate based on chipload.
    Art and Creativity - Collide with the Functionality of CNC - priceless
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