Thread size on the Elgeet 135/4.5 ?

Discussion in 'Enlarging' started by jjphoto, Jan 27, 2011.

  1. jjphoto

    jjphoto Member

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    I can't figure out what the thread is on the Elgeet 135/4.5. Does anyone know?

    It seems to be 32 or 32.5mm (or so) and I can't tell if it's 0.75 or possibly even finer. Then again it might not be metric at all as 1 1/4"=31.75mm. There doesn't seem to be much info on these things so any advice would be appreciated.

    Thanks
    JJ
     
  2. Ian C

    Ian C Member

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    I’m unsure about the Elgleet lens, but the other US made enlarging lenses that I’ve examined use common fractional inch sizes and inch-based thread pitch.

    For example, I have a 162mm f/4.5 Enlarging Raptar, it’s flange, as well as a flange only from a smaller Raptar of unknown focal length.

    The 162 Raptar has mounting thread of 1.994” outside diameter. It appears to be 2” x 30 threads per inch 60° unified v-thread. The 30 tpi thread gage fits well, while no similar metric pitch fits properly.

    The smaller Raptar flange has 1 3/8” diameter x 30 tpi 60° unified v-thread.

    All of the US enlarging lenses I’ve examined are marked “Made in Rochester, NY”, so it’s not surprising if they used a common threading standard.

    From your comments about the thread size, it’s likely 1.25” diameter x 30 tpi.

    1.25” = 31.75mm, which is approximately your estimated diameter of 32mm to 32.5mm.

    Given the scarcity of flanges in these sizes, it’s advisable to buy a lens if, and only if, the proper flange is included.
     
  3. jjphoto

    jjphoto Member

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    Thanks for your help. I'll try to get a 1.25" flange and see how that goes.

    Truer words were never been spoken!

    JJ
     
  4. Jim Jones

    Jim Jones Subscriber

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    The 1944 ASA standard specifications for photo equipment lens threads includes 1.25 inch and 30 TPI, but also states that other threads may be used.
     
  5. jjphoto

    jjphoto Member

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    Great! Thanks very much.

    JJ