Help calibrating Mitotoyu dial caliper 505-626

Discussion in 'Reloading Forum (All Calibers)' started by CT10ring, Feb 16, 2019.

  1. CT10ring

    CT10ring Gold $$ Contributor

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    At some point, this caliper "became" off by about .015" Maybe took a tumble...?
    Have been using a Starrett digital, but would like to use this, too.

    Any idea how to adjust recalibrate?

    any info appreciated. mititoyu.jpg
     
  2. madmixerman

    madmixerman Gold $$ Contributor

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    Looks like you loosen the thumbscrew and turn the dial to zero.
     
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  3. watercam

    watercam Gold $$ Contributor

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    You might check and see if you have accumulated any foreign material on the inside faces of your blades. Wipe them with a clean soft rag and check again. Then adjust your dial to 'O' by loosening the thumb screw at the bottom and rotate the dial. Tighten thumb screw but only just enough. Don't over do it.
     
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  4. CT10ring

    CT10ring Gold $$ Contributor

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    yes, easy to do that, just seems odd to have the dial canted. 0 was at 12 & 6 o' clock earlier...
    thx--
     
  5. geo.ulrich

    geo.ulrich beware of owner Gold $$ Contributor

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    It jumped a tooth on the rack gear, run it back and forth see if it continues to jump. If it does you need to clean gears. also if it was dropped hard it could have bent a gear pinion.
     
  6. jepp2

    jepp2 Gold $$ Contributor

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    Here is how to re-clock them.

     
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  7. CT10ring

    CT10ring Gold $$ Contributor

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    good info thx all ! Mitotoyo can't be calibrated as the better Starrett, tho.

    I had to slide / remove the dial + assembly 1 -- completely from the other set assembly 2 ( geared rack).

    Then reengage the gears/pinion 4-5 times - trial & error until they were within .005" at closed position.
    Then loosen the 3 screws backside to fine tune the rack. Then tighten the back screws while at 0.00 in closed position.

    Matches my Starrett digi measurements exactly. and no parts left over.

    Now I'm going to smash a maul into some doug fir 18" rounds...
    Mitotoyo_2.jpg
     
  8. daleboy

    daleboy Silver $$ Contributor

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    Sounds like quite a project,glad it had a happy ending...cool that you had no leftover parts,I always hate when that happens.
     
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  9. CT10ring

    CT10ring Gold $$ Contributor

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    don't think anyone is sweating my caliper crisis :)
    but maybe this post will be a reference here in the future.
    glad to have it back in use. a well made, useful tool is not to be underestimated.
     
  10. jonbearman

    jonbearman I live in new york state,how unfortunate ! Gold $$ Contributor

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    Mitutiyo used to pit a small piece of copper shim stock in your case. It is a weird shape and what you do if you had it is drive the pinion up onto the copper foil and slide one way or the other to reset your zero. I have the same one and it came with the tool and had to use it occasionally to reset my zero.
     
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  11. CT10ring

    CT10ring Gold $$ Contributor

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    Well that is the "problem" and answer! No tool here, but should be good for awhile. thanks-
     
  12. Rustytigwire

    Rustytigwire Gold $$ Contributor

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    Right Johnbearman.
    My machinist brother gave me a 6" Mit in 81, said dont lose that little copper thang. Well i did...
     
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  13. Guybo

    Guybo

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    All i've ever used is Mitutoyo calibers and they have all calibrated the same way. Any small straight rigid item (bent paper clip) will work if you don't have the tool that came with the caliper. There should be a small hole (may be square) either at the top of the dial or at the bottom. You slide the caliper open and line the dial needle up on zero, insert the tool and apply downward pressure, hold downward pressure and slowly close the caliper. Release the pressure, dial should stay at zero. You can check the calibration with gage blocks or any known measurement.
     
    Last edited: Mar 2, 2019
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  14. granite1

    granite1 Gold $$ Contributor

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    Thanks for the info! I just fixed my Mitutoyo caliper that I thought was toast.
     
  15. CT10ring

    CT10ring Gold $$ Contributor

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    dam, you guys rock. I'm no expert, but this feels like a really good tool.
    good to have it back.
     

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