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Thread: Century 8A?

  1. #11

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    Re: Century 8A?

    Quote Originally Posted by slerman View Post
    That is very helpful Jim. I had ordered a 20 tooth .25" bore pinion as a guess. Any idea what's the right pitch?Attachment 201741
    I’ll work on it tomorrow. Too cold t go back upstairskr

  2. #12

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    Re: Century 8A?

    Quote Originally Posted by slerman View Post
    That is very helpful Jim. I had ordered a 20 tooth .25" bore pinion as a guess. Any idea what's the right pitch?Attachment 201741
    Made it back upstairs. 32 pitch. I'd err on the side of too many teeth not too few or diameter might be shy enough for it to "skip".

  3. #13

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    Re: Century 8A?

    Thanks for braving the cold Jim! Haven't found one yet that exactly meets that spec. When it is delivered, I'll carefully try out the one I ordered. It is 32 pitch. May be able to shim the plate the positions the shaft to avoid any skipping.

  4. #14

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    Re: Century 8A?

    Been trying to date the camera by serial #-- 51567-- on the rear frame. The various online sources don't seem to match up. Any ideas?Click image for larger version. 

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  5. #15

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    Re: Century 8A?

    No idea on ages or how long they were catalogued. Mine has the bigger wood knobs on everything. Also the shaft on mine goes all the way from side to side so that both knobs turn when it's rolling out or in. Mine is in the 125XXX number so likely newer than yours. Also the way the geared movements work is less machined and probably cheaper to produce. All this stuff changed during long runs.
    Last edited by Jim Galli; 17-Mar-2020 at 09:49.

  6. #16

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    Re: Century 8A?

    Quote Originally Posted by slerman View Post
    That is very helpful Jim. I had ordered a 20 tooth .25" bore pinion as a guess. Any idea what's the right pitch?
    The tooth pitch is measured from the rack. The number of teeth on the gear [pinion] is the circumference of the outside diameter divided by the rack pitch and then reduced to the next, or next but one whole, number. Since the number of teeth and pitch are measured at the pitch diameter of the gear [pinion] which is smaller than its outside diameter.

    Conversely, if you know, or can guesstimate, the pitch diameter of the gear/pinion then (pitch diameter x pi [3.1416])/ number of teeth gives the pitch

    regards
    Tony
    Last edited by tonyowen; 18-Mar-2020 at 09:22. Reason: erroneous comma, extra paragraph

  7. #17

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    Re: Century 8A?

    Tony, never would have figured that out on my own. Thanks, Scott

  8. #18

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    Re: Century 8A?

    Quote Originally Posted by slerman View Post
    Tony, never would have figured that out on my own. Thanks, Scott
    You're welcome
    A point of clarification - to measure the pitch of the teeth on the rack - measure over a 'large number of teeth' then divide that value by one less than the number of teeth. The more teeth over which you measure will give a more precise value of pitch --- (distance measured over N teeth)/[N-1]
    regards
    Tony

  9. #19
    multi format
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    Re: Century 8A?

    Quote Originally Posted by slerman View Post
    John, Looks like some of the photos of Centurys online. The molding in the front. the knurled knobs in the back--although others seem to have a wood, not brass, central track lock. The back also has the raised piece at bottom that, the back's groove fits into. The back tilt and swing seems the same. What doesn't match with yours? Hmmm. Thanks, Scott

    Attachment 201740
    hi Scott

    never mind, it was the way you photographed it !
    John
    enjoy your coffee

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