SMPTE specification for sprocket concentricity?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Tj Hopland
    Pro Film Handler
    • Jun 2025
    • 264
    • Minneapolis, MN

    #1

    SMPTE specification for sprocket concentricity?

    I assume there was a specification and tolerance for the concentricity (roundness) of sprockets especially the intermittent sprocket? Not that we really have a lot of options these days but I was curious what the spec was.
  • Josh Jones
    Pro Film Handler
    • Feb 2024
    • 153
    • McKinney, TX

    #2
    The dimensions of KS holes are defined in SMPTE 237. https://pub.smpte.org/doc/st237/2003...stable2015.pdf
    ​

    Comment

    • Jim Cassedy
      Film God
      • Jan 2020
      • 1450
      • San Francisco

      #3
      Originally posted by Josh Jones
      The dimensions of KS holes are defined in SMPTE 237.​
      > Maybe I'm interpreting the question wrong, but I think TJ was looking for the
      the specifications of the actual intermittent SPROCKET. . not the sprocket
      holes, but I could be wrong. I think I've seen the physical specs for all the
      sprocket 'wheels' published in a big, old SMPTE reference book I've
      got somewhere, but I'm not going to be at home most of this weekend.

      Comment

      • Tj Hopland
        Pro Film Handler
        • Jun 2025
        • 264
        • Minneapolis, MN

        #4
        Correct, I recently replaced an intermittent sprocket and thought maybe was more picture movement than before so I checked it with a dial indicator and the replacement had more wobble to it than the one I took out. Turned out a decent amount of the movement apparently was in the loop I was using, it sucks not having an unlimited supply of fresh PA-35. I'm pretty sure they have since done a preview screening and didn't hear any complaints so I don't think its a problem per say I was mostly curious what the spec was.

        Comment

        • Josh Jones
          Pro Film Handler
          • Feb 2024
          • 153
          • McKinney, TX

          #5
          Sorry, I misread the OP. The specs sheets for sprockets don't specify runout, only sprocket tooth profiles and other dimensions.
          Attached Files

          Comment

          Working...