Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,283   Posts: 1,534,926   Online: 860
      
Results 1 to 3 of 3
  1. #1

    Join Date
    Sep 2002
    Location
    Lehi, UT
    Shooter
    4x5 Format
    Posts
    21

    Focusing Mechanism

    I need some advice of a mechanical nature. I'm in the design phase of building my first camera, and I'm confused about how the focus and lock-down knobs work on the focusing rail. I'm implementing a rack and pinion focusing mechanism, but I'm not sure how to add two focusing knobs to the ends of the shaft, while at the same time providing some way to 'lock' the shaft so it can't turn? Can anyone shed some light on this for me?

    Thanks,

    Curtis

  2. #2
    glbeas's Avatar
    Join Date
    Sep 2002
    Location
    Roswell, Ga. USA
    Shooter
    Multi Format
    Posts
    3,307
    Images
    109
    On the two field cameras I own the shaft had a threaded end with a knob/nut on it opposite the focusing knob. Tightening this will squeeze the bed and lock down movement of the shaft. The alternate would be to have a threaded lock screw at right angles to the shaft to immobilize it or a cammed lever that will wedge the standard in place.
    Gary Beasley

  3. #3

    Join Date
    Feb 2004
    Location
    Minnesota Tropics
    Shooter
    Multi Format
    Posts
    735
    It's a tricky thing to incorporate the lock in the knob and spool (shaft), so consider another way. For example, you could put a threaded hole in the front/rear standard by the rail and have a nylon ball in the shaft backed up by a bolt with knob at the end (they sell the knobs w/bolts at ACE Hardware). A tiny bit of pressure on the shaft seats the nylon ball just enough. You should not need much pressure at all.



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin