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Leica Tribrach Optical Plummet Adjustment

Discussion in 'General Land Surveying' started by amdomag, Aug 25, 2012.

  1. amdomag

    amdomag 4-Year Member

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    Hi guys!

    I am quite confused with the pattern and direction on how adjustment screws of my Leica tribrach are to be operated as the cross hairs movement appears not consistent when I tried it my way. As far as I can remember, the turning of screws shall be in alternate fashion but it seems not working particularly when trying to reverse the movement.

    Anybody can help me with a link? By the way, I am using the SECO adjustment ring.

    Thank you.
     
  2. Dave Karoly

    Dave Karoly 5-Year Member

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    The Leicas I have adjusted have a screw on each side and top and bottom if I remember right. You loosen one and tighten the opposite like on an old four footscrew transit.

    If that isn't working for you then maybe one or more screws are broken or stripped. The newer tribrachs come with tiny little screws which are really cheap and weak.
     
  3. amdomag

    amdomag 4-Year Member

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    Are all the screws necessarily tight when calibration is achieved?
     
  4. Jim Frame

    Jim Frame 5-Year Member

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    > Are all the screws necessarily tight when calibration is achieved?

    I think "snug" is a better term than "tight" in this context. You're dealing with finger-tip pressures rather than the fist-and-wrist variety. The screws want to be turned enough to take out the lash and resist loosening under normal vibration, but you don't want to flirt with the yield point of the material.
     
  5. Jimmy Cleveland

    Jimmy Cleveland 5-Year Member

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    You have to make sure that when you tighten one screw, you loosen the opposite one. It took me a little tinkering before I caught on to the pattern. Having said that, I don't have any Lieca tribrachs, but I would think that the principles are close to being the same.
     
  6. Jim Frame

    Jim Frame 5-Year Member

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    > You have to make sure that when you tighten one screw, you loosen the opposite one.

    I think the reverse procedure is preferable: loosen one, then tighten the opposite. Otherwise, you risk stripping the screw in an effort to move the crosshair.
     
  7. Mark Mayer

    Mark Mayer 5-Year Member

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    FWIW, Leica switched manufacturers and design on their tribrachs in about 2005 +/-? . Before that their tribrachs were made in Austria. Newer ones are made in Czechoslovakia/Czech Republic. The Austrian ones were of much better quality. The two have distinctly different adjustment appuratus.
     
  8. Dave Karoly

    Dave Karoly 5-Year Member

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    We have a post-2005 TCRP1203+ with a tribrach (no O.P.) labeled "Made in Hungary."

    The S6 has an even cheaper looking tribrach on it, though.
     
  9. Jimmy Cleveland

    Jimmy Cleveland 5-Year Member

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    Jim,

    You are CORRECT! Thanks for that. I would hate for someone to mess up a good tribrach.

    Jimmy
     
  10. Mark Mayer

    Mark Mayer 5-Year Member

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    I may have confused my eastern European countries.
     
  11. R.J. Schneider

    R.J. Schneider 5-Year Member

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    Amdomag,
    Are you trying to tell us the image is inverted ?
     
  12. R.J. Schneider

    R.J. Schneider 5-Year Member

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    I think you should get points for at least spelling Checko.. Czheko..
    That country adjacent Yugoslavia, correctly.
     
  13. Supply Guy

    Supply Guy 3-Year Member

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    White paper from Leica about their tribrachs.

    http://www.leica-geosystems.com/downloads123/zz/accessory/accessories/white-tech-paper/White%20Paper%20Tribrachs_en.pdf

    But no adjusting instructions.
     
  14. Paul in PA

    Paul in PA 5-Year Member

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    Back Off Upper/Lower A Hair, Before Adjusting Left/Right

    To allow reticle to slide.

    Then loosen one side before tightening other side.

    Same but different to adjust upper/lower.

    Once it is adjusted, snug up all around.

    Paul in PA
     
  15. amdomag

    amdomag 4-Year Member

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    Thank you guys!

    I just finally figured it out, of course with your help.

    :-) :-)
     
  16. Mike Lacey

    Mike Lacey 5-Year Member

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    Where are the screws on your tribrach located? I have a Wild GDF22, and there only seems to be two screws on the right side of the eye piece. Nothing on the top, bottom or left. I was wondering what the procedure is for the GDF22.
     

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