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IndustryArena Forum > WoodWorking Machines > DIY CNC Router Table Machines > My machine should be more accurate right?
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  1. #1
    Join Date
    Feb 2007
    Posts
    167

    My machine should be more accurate right?

    Im running 1.8 degree steppers with 10 microstepping drives. I am running them via a 1.2" diametrical pitch spur gear that is heavilly spring loaded on the track (to eliminate backlash). I have calculated my steps per unit to be 530.786 approximately.

    I ran a program that cut 1" square "pockets" in each of the 4 corners of the machine (4'x8'). I am seeing squares that are averaging around .9"x.9"

    Do I have backlash in my machine? Are my steps per unit for Mach 3 wrong? Is there something I am overlooking? Thanks in advance!

  2. #2
    Join Date
    Feb 2007
    Posts
    4553

    Post

    Most likely the step per inch are not set correctly.

    There is a utility built in to Mach3 that will calculate the exact settings.

    It is located on the settings page of Mach3

    See the attached jpg for the button location.

    Jeff...
    Attached Thumbnails Attached Thumbnails Set steps per unit.JPG  
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  3. #3
    Join Date
    Feb 2007
    Posts
    4553

    Smile

    Hoss made a great video of how to use it.

    [ame="http://www.youtube.com/watch?v=XkO5tc-jSxw"]YouTube - Improved Mach 3 Axis Calibration[/ame]
    Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.

  4. #4
    Join Date
    Apr 2009
    Posts
    9
    Quote Originally Posted by idtkid View Post
    Im running 1.8 degree steppers with 10 microstepping drives. I am running them via a 1.2" diametrical pitch spur gear that is heavilly spring loaded on the track (to eliminate backlash). I have calculated my steps per unit to be 530.786 approximately.

    I ran a program that cut 1" square "pockets" in each of the 4 corners of the machine (4'x8'). I am seeing squares that are averaging around .9"x.9"

    Do I have backlash in my machine? Are my steps per unit for Mach 3 wrong? Is there something I am overlooking? Thanks in advance!
    Is the program to cut the squares set up to go all at once? That is, does that single program cut one corner, travel to the next corner, cut another corner, etc.?

    If so, and if the placements of the squares are accurate, then the error is likely not from your steps per inch, but instead your compensation for the cutting tool diameter, or some other setting.

    However, as jalessi has said, it is otherwise most likely due to an incorrect steps per inch calculation.

  5. #5
    Join Date
    Feb 2007
    Posts
    167
    /\ each square had its own datum and was run seperately, I will try the calibration tool in mach 3, thanks guys, tons of responses real fast!

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