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  1. #1

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    Rebuilding T-P Roller Blind Shutters

    Wow... what a cool forum. And, Sean... what a cool camera!

    I have a couple of old plate cameras, two different sizes, and a bunch of plate holders that I picked up in England many years ago. Not long ago I bought a T-P tripod that fits the proprietary (I think) tripod mount.

    They've been gathering dust in a closet because the Thornton Pickard shutters are shot. The roller blind material is hard and crusty, and the axles for the rollers are a bit rusty. One day I plan on tearing into them and rebuilding them, but haven't really much of a clue about how they are constructed. My hope is that they are relatively self-explanatory.

    Does anyone have experience/advise regarding the rebuild of these shutters?

    Can anyone explain how the air release works? I seem to recall reading somewhere that it was a closed rubber tube that fit under the half-round clip on the left side of the shutter and somehow expanded to cause the shutter to trip.

  2. #2

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    Brian,
    They are relatively simple. There are two axles, one which has an internal spring (I have no idea what sort) and one which is solid. The sprung loaded one has a ratchet on it that allows you to change the tension on the spring and thus the shutter speed.

    The blind is attached to both axles, either glued or sewn. There is a thin cord attached to a pulley on the unsprung axle. Pulling on the cord winds the blind onto the unsprung axle against the tension of the spring in the other axle. On top of the unsprung axle is a small cog which connects to a larger gear which has a ratchet attached. The large lever on top acts as a stop against the ratchet. This prevents the blind rewinding when you let go of the string.

    Lifting the lever up disconnects the ratchet and allows the sprung axle to rewind the blind at high speed. The clever part is that there are two stops on the ratchet. The first stops the blind fully open while the second winds it closed again and sets the shutter. The lever has two positions, T & I. When you move it to T the ratchet will engage both stops, so firing the sutter opens it and firing it again closes it. When you move the lever over to I it is raised and acts against a different stop (there is only one) and thus does the complete cycle in one hit.

    The levers on mine have a little hole in them which the shutter release connects to. You could tap that so that a modern cable or bulb release can be screwed in place.

    All of this I have worked out just by looking at them and carefully disassembling them. Having posted on the other thread I decided to order the shutter cloth from http://aki-asahi.com/store/ and see how it goes. If you look at the procedure at http://aki-asahi.net/store/html/shut...l/inst/01.html you should get the idea.

    I'm not sure whether your rusty axles will be a problem. I still have to find a source for the cord. String is not an acceptable replacement, it needs to be thin and strong and the string tends to unravel. The orginal cord is woven, not twisted which seems to be the difference.

    hope that helps,

    Paul

  3. #3

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    Thanks, Paul, for the very informative answer. I'll have to take another look at the shutter now that you've explained it. I figured out the "pull the cord" part and the release bar, but never quite finished working out the rest of how these shutters worked.

    Somehow I thought I recalled a dial with speeds. That is what really had me confused. As I said... I'll definitely have to have another look. Your description of "T" and "I" is more like I imagined it working!

    The rusty axles might end up being the major problem. I'm guessing that if it's only surface rust I can clean and polish, but if it's worse maybe I'll have to attempt replacing them. I'm also thinking that the holes they fit in can be bushed with brass, if they aren't already, if the holes are worn.

    You just may have given me the courage to tear it apart and have a closer look. Thanks again!

  4. #4

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    Okay Paul, I see where yo mention the tension knob for adjusting shutter speed. Thanks...

  5. #5

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    [QUOTE=paul ewins]Brian,
    They are relatively simple. There are two axles, one which has an internal spring (I have no idea what sort) and one which is solid. The sprung loaded one has a ratchet on it that allows you to change the tension on the spring and thus the shutter speed.

    The blind is attached to both axles, either glued or sewn. There is a thin cord attached to a pulley on the unsprung axle. Pulling on the cord winds the blind onto the unsprung axle against the tension of the spring in the other axle. On top of the unsprung axle is a small cog which connects to a larger gear which has a ratchet attached. The large lever on top acts as a stop against the ratchet. This prevents the blind rewinding when you let go of the string.

    Lifting the lever up disconnects the ratchet and allows the sprung axle to rewind the blind at high speed. The clever part is that there are two stops on the ratchet. The first stops the blind fully open while the second winds it closed again and sets the shutter. The lever has two positions, T & I. When you move it to T the ratchet will engage both stops, so firing the sutter opens it and firing it again closes it. When you move the lever over to I it is raised and acts against a different stop (there is only one) and thus does the complete cycle in one hit.

    The levers on mine have a little hole in them which the shutter release connects to. You could tap that so that a modern cable or bulb release can be screwed in place.

    All of this I have worked out just by looking at them and carefully disassembling them. Having posted on the other thread I decided to order the shutter cloth from http://aki-asahi.com/store/ and see how it goes. If you look at the procedure at http://aki-asahi.net/store/html/shut...l/inst/01.html you should get the idea.

    I'm not sure whether your rusty axles will be a problem. I still have to find a source for the cord. String is not an acceptable replacement, it needs to be thin and strong and the string tends to unravel. The orginal cord is woven, not twisted which seems to be the difference.

    hope that helps,

    Paul[/QUOTE

    Admittedly the blinds are usually petrified but I have had some success patching them with diluted Plasti-dip. There is also a braided fishing line sold which might do to replace the strings.
    Mark
    Mark Layne
    Nova Scotia
    and Barbados

  6. #6
    Ole
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    I've somehow got hold of three of these things, of which two are fine and one is for parts. The "parts" one has no other problem than that the speed changing system is rusted stuck. Completely stuck. It works fine, but only at 1/30.

    They also have interchangable front panels (two of them do), and I've got an extra front panel. So that's three different lens threads on the good "threadmount" one. The last one has a "baffle", meant for front mounting on a lens of suitable diameter. Just push it on, and it will keep in place for long enough to take a picture.

    I don't know if this goes for all TP shutters, but the front panel on mine just lifts off to give access to the workings.
    -- Ole Tjugen, Luddite Elitist
    Norway

  7. #7

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    Ole, I have three (two different sizes) that have the lensboard arrangement but I remember seeing one that didn't have the removable front. I assume that one was for mounting on the front of the lens.

    Mark, I'll check out the braided fishing line. It sounds like a good substitute.

  8. #8

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    I have two shutters, with the same lens mount. The two cameras i got came from the same person and he appears to have shared one lens between them.

    One shutter has two brass "L" hooks that twist and release the front to expose the inner works. The other, marked as a "Sanderson shutter" has a front that is somehow fixed and not easily removable. There is a screw on the side that has no apparent purpose... perhaps that holds the front on, I don't yet know.

    Out of curiousity, I searched the European patent office for Thornton-Pickard shutter patents. I found several describing "improvements" to the roller-blind shutter, but I couldn't find the original 1898 (I think) patent.

  9. #9

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    Quote Originally Posted by paul ewins
    Mark, I'll check out the braided fishing line. It sounds like a good substitute.
    I didn't even know there was such a thing. I know very little about fishing!

    I was going to look at the fabric & sundries shop, in the hopes that something like this cord is used for embroidery or other "fabric arts". I know very even less about embroidery that I know about fishing!

  10. #10

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    Okay, I've rebuilt my shutter and put it all up in a series of pages at:
    http://members.optusnet.com.au/~paul...tp_shutter.htm

    Please let me know of any typos (bound to be lots) and any additions or corrections you feel it needs. FWIW, I never did get around to finding the cord that I wanted. For this rebuild I used 1mm model ship rigging which I had ordered sight unseen. It turned out to be just like normal thread but does the job. Next time I might try (non waxed) leather working thread which can be bought thicker than usual dress-making thread.

    The shutter cloth I bought from Japan seems first rate and I have enough left over for another three or four shutters.

    Next job is to find a source of very small woodworking screws. If anybody knows of a source in Australia I would be grateful of the information but I suspect I will have to go with someone like micro-tools that does international mail order.

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