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IndustryArena Forum > MetalWorking Machines > Tormach Personal CNC Mill > .007" egg-shaped holes while circle-milling
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  1. #1
    Join Date
    Nov 2013

    .007" egg-shaped holes while circle-milling

    I'm getting about .007" egg-shaped holes while trying to circle mill.
    It appears to be happening in the X Axis.
    Does this sound like a backlash issue, and what needs adjusting?

  2. #2
    Community Moderator Jim Dawson's Avatar
    Join Date
    Dec 2013

    Re: .007" egg-shaped holes while circle-milling

    It does sound like a backlash issue. The normal causes are: 1) loose motor coupling, 2) thrust bearing adjustment, 3) worn ball nut/screw.
    Jim Dawson
    Sandy, Oregon, USA

  3. #3
    Join Date
    Jan 2018

    Re: .007" egg-shaped holes while circle-milling

    0.007" that's like 0.17 ish in mm. That's a lot for it to be a backlash problem alone.
    Sounds like something is loose or needs a lot of adjustment.

  4. #4
    Flies Fast
    Join Date
    Dec 2008

    Re: .007" egg-shaped holes while circle-milling

    Which axis has the correct size for the diameter ? .... that is the axis that doesn't have a problem.
    Are there flats where the axis changes direction ?

    As Daz says, check all items that are on that axis, I've seen bodgy work where some builder used pointed set screws instead of keys on drive mechanisms.

  5. #5
    Join Date
    Nov 2013

    Re: .007" egg-shaped holes while circle-milling

    Y axis is correct, X axis is over-sized .007".
    I'm guessing it's the Thrust-Bearings.

  6. #6

    Re: .007" egg-shaped holes while circle-milling

    Not on a Tormach, but the last time I had an issue like this the ballnut was loose in the carriage. Easy fix.

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