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  1. #11
    medform-norm's Avatar
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    Quote Originally Posted by Tom Hoskinson
    Hi Norm, what is the thread diameter and pitch on your old 150mm G-Claron?
    Hi Tom,
    "thread diameter" and "pitch" are words I can use in a discussion without blowing my cover, but which I do not completely understand nonetheless, if I'm honest about it. Where do I measure the thread diameter? Where do I start to count if I want to calculate pitch? What good is this information going to do me? We normally work by experience and mechanical insight rather than mathematics and calculus. Seems to be a matter of which parts of your brain are more active than others. So, please explain your words like if you would to a 3 year old.

  2. #12

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    Hope this helps, Norm.

    Threads
    Threads are an integral part of many mounting components - like bolts, screws and lenses.

    English notation is thread diameter (inches) x threads per inch.

    Metric notation is thread diameter (mm) x thread pitch (mm) (e.g. 42mm x 0.75mm).

    Lens Thread Diameter
    Lens thread diameter is the outer diameter of the threaded portion of the lens body (or lens element).

    Thread Pitch
    Metric threads are specified with a thread pitch instead of a thread count. The thread pitch is the distance between threads expressed in millimeters (measured along the length of the threads). For example a thread pitch of 1.5 means that the distance between one thread and the next is 1.5mm. In general smaller diameter devices have finer thread so they have lower thread pitch.
    Tom Hoskinson
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    Everything is analog - even digital :D

  3. #13
    medform-norm's Avatar
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    Quote Originally Posted by Tom Hoskinson
    Hope this helps, Norm.

    Threads
    Threads are an integral part of many mounting components - like bolts, screws and lenses.

    English notation is thread diameter (inches) x threads per inch.

    Metric notation is thread diameter (mm) x thread pitch (mm) (e.g. 42mm x 0.75mm).

    Lens Thread Diameter
    Lens thread diameter is the outer diameter of the threaded portion of the lens body (or lens element).

    Thread Pitch
    Metric threads are specified with a thread pitch instead of a thread count. The thread pitch is the distance between threads expressed in millimeters (measured along the length of the threads). For example a thread pitch of 1.5 means that the distance between one thread and the next is 1.5mm. In general smaller diameter devices have finer thread so they have lower thread pitch.
    Well explained, Tom, that couldn't have been clearer! All the mystery has cleared up like a spring fog in the morning sun. Thanks a lot.

    The G-Claron front and back elements both have a Lens Thread Diameter of 2,85mm or 1 1/8 inch. For measuring the pitch we don't have the right tools. It seems to have 4 threads on 1/16th of an inch = 64 thread per inch. (Does that sound right?).

    Does this help to find the right shutter in any way? We guess it will very likely be a german/metric shutter, and not an english one.

    Regards, Norm

  4. #14

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    Quote Originally Posted by medform-norm
    Well explained, Tom, that couldn't have been clearer! All the mystery has cleared up like a spring fog in the morning sun. Thanks a lot.

    The G-Claron front and back elements both have a Lens Thread Diameter of 2,85mm or 1 1/8 inch. For measuring the pitch we don't have the right tools. It seems to have 4 threads on 1/16th of an inch = 64 thread per inch. (Does that sound right?).

    Does this help to find the right shutter in any way? We guess it will very likely be a german/metric shutter, and not an english one.

    Regards, Norm
    Norm, 1 1/8 inch is 28,57mm. 64 threads per inch indicates a metric pitch of about 0,4mm

    If your thread diameter is actually 29,5mm that equals the thread diameter of a current 150mm G-Claron and it is also the thread diameter of the Copal 0 shutter.

    The thread pitch of a current 150mm G-Claron is 0,5mm. 0,5mm is also the thread pitch on the Copal 0.

    http://photoweb.net/pw_tech/copal.html
    Tom Hoskinson
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  5. #15
    medform-norm's Avatar
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    Quote Originally Posted by Tom Hoskinson
    Norm, 1 1/8 inch is 28,57mm. 64 threads per inch indicates a metric pitch of about 0,4mm

    If your thread diameter is actually 29,5mm that equals the thread diameter of a current 150mm G-Claron and it is also the thread diameter of the Copal 0 shutter.

    The thread pitch of a current 150mm G-Claron is 0,5mm. 0,5mm is also the thread pitch on the Copal 0.

    http://photoweb.net/pw_tech/copal.html
    Very nice table with data. Bookmarked that. I suppose we really have an older G-claron, as the diameter is exactly 1 1/8 inch. Someone on another forum reported a difference in diameter between older and newer G-Clarons. As to the thread pitch: I won't know till we measure it correctly.

    That being said, it seems to fit a Synchro Compur nicely. You might not by any know where I can thread pitches of Synchro's?

    I'd prefer getting a Synchro if possible, Copal shutters tend to be little on the expensive side.

  6. #16
    David H. Bebbington's Avatar
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    Good old-fashioned repairmen are getting scarce (which may be why Grimes charges so much).
    If you specifically want someone to dismantle and clean a lens, try:

    Optical Instruments (Balham) Ltd
    Unit 39
    Neville Court
    27 – 43 Neville Road
    Croydon
    Surrey CR0 2DS
    UK
    Tel.: 020 8664 9799

    To give you an example, they are currently dismantling and partly repolishing and coating a 12" f4.5 Dallmeyer Serrac for me and also servicing the #5 Compound shutter. I have wasted money in the past trying to save lenses that were beyond hope, but one like this I think is worthwhile - couldn't find anyone else to do it. Dismantling cemented groups seems to be the problem.

    PS:
    http://www.gandolficameras.com/
    have made parts for old view cameras for me in the past - not cheap, but good.
    For threaded adapters, would echo earlier recommendation of srb film services. I think fundamentally they will do anything that can be done with a lathe. It can be worth asking local machinists - I once had a local workshop make a lot of lens panels and bellows frames for a De Vere monorail - I caught them when they weren't busy and they did a great job quickly for not much money. Shortly afterwards they got a really big contract and couldn't take any more work!

  7. #17

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    Um, David, you helped me remember that when I asked Cooke Optics about repairing one of my TTH lenses they recommended http://www.truelens.co.uk/index.htm

  8. #18
    David H. Bebbington's Avatar
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    Quote Originally Posted by Dan Fromm
    Um, David, you helped me remember that when I asked Cooke Optics about repairing one of my TTH lenses they recommended http://www.truelens.co.uk/index.htm
    I'm sure they're good, Dan, but their prices seem to be pitched at the professional motion picture market, whereas for example the Serrac repair and shutter overhaul I mentioned will cost around £150 - enough, but affordable!

  9. #19
    medform-norm's Avatar
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    Succes with Zodelar

    Hi Guys,
    while you have been giving away good tips, we took Zodelar to Mr. Rollei Holland and he helped us take the lens apart so it could get cleaned- for free! His trick was to use something called Bison Thinning Fluid, applied very sparingly with a thin tweezer on the ring that was stuck and 1 minute later the Zodelar gave up it's resistance and opened up like there never had been a problem. Now it's a lot cleaner. Plus we could get a look at the lens design. It's probably a Tessar type. We took two test shots, but forgot the lightmeter and back home found out we had underexposed. Another DUH moment. Next time better. It looks like a promising lens.

    Mr. Rollei Holland is a very nice man who can do a lot of repairs on 35mm and medium format cameras plus the occasional shutter. He admitted honestly not to know a lot about lens design and optics. Nor did he know a Dutch equivalent Grimes - he only mentioned a place that had totally screwed up a lens for him! I'll reserve a black list for another thread.

    G-Claron update: reading the outer thread diameter by measuring from the ridges of the threads, not the cavities, gets us to 29,5 mm - so maybe Tom was right after all. Then we would have a newer model G-Claron which was made in '74, according to the Schneider archive. Perhaps it's possible, who knows?

  10. #20

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    Quote Originally Posted by medform-norm
    I'd prefer getting a Synchro if possible, Copal shutters tend to be little on the expensive side.
    True, but you can get spare parts from Copal for the Copal shutters.

    Compur is no longer in business, so spare part availability can present a serious problem (unless you are capable of making spares).

    IMO, Copal's aperture control design (logarithmic) is superior to Compur's (linear).
    Tom Hoskinson
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    Everything is analog - even digital :D

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