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Sirius Glass
Joined: 06 Jun 2010 Posts: 162 Location: Southern California
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Posted: Sun Oct 16, 2011 2:41 pm Post subject: 4"x5" Graflex shutter dimensions |
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Does anyone have the 4"x5" Graflex shutter dimensions so I can build a new shutter without removing and damaging the shutter in the camera?
Steve _________________ Nothing beats a good piece of glass. |
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mopar_guy
Joined: 07 Aug 2008 Posts: 126 Location: Washington, the State
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Posted: Sun Oct 16, 2011 5:40 pm Post subject: |
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Steve,
I have seen this question asked before on this board, and the replies are generally to use the existing shutter as a pattern to fabricate a new one.
Dave |
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45PSS
Joined: 28 Sep 2001 Posts: 4081 Location: Mid Peninsula, Ca.
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Posted: Sun Oct 16, 2011 7:41 pm Post subject: |
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While all Graflex SLRs are a variation on a theme and therefore very similar, there are differences between models in any format.
Due to differences in bodies of different models in the same format each model probably has its own curtain.
If you have a dried out curtain it is the rubber coating that is brittle not the cloth. Adhesive remover may need to be applied to the top roller to get the curtain loose.
Once the curtain is out of the camera soak a section at a time in lacquer thinner for 2 to 3 minutes them lay on a flat, firm surface and scrape the rubber off with a wide drywall knife keeping the blade 90 degrees to the curtain and holding the curtain behind the blade as you scrape. The lacquer thinner dissolves the rubber coating to a thick goo that comes off easily. Hard spots soften when resoaked. Wear furniture stripping gloves or similar. A 14 inch to 16 inch long shallow baking dish works well for soaking the curtain. The lacquer thinner needs to be 1/4 to 3/8 inch deep in the soak container. Work in a well ventilated area.
Once the curtain has been fully stripped wash it in warm soapy water, rinse thoroughly and hang to dry with weight on the bottom (4 or 5 wood clothes pins work). Once dry lay out and measure the overall length and the distances between the aperture slots.
Cut the new curtain blank 3 to 6 inches longer than the original.
Draw the aperture slots starting with the O slot onto the rubber side. The extra length will be at the 1/8 aperture/tension roller end.
Once drawn install the curtain blank into the camera, rubber side out, and align the wind key with the slots. Tension the curtain. Wind the curtain to each aperture and check
1. aperture line is above the top image box guide roller when wound to that aperture.
2. aperture line is below the lower image box guide roller when the M lever is held back in the full release position. The curtain will go another 1/4 to 3/8 inch further down when the M lever is released which is the same as recocking the mirror.
Due to curtain thickness differences you may have to adjust the distances between aperture openings by 1/8 to 3/16 inch. The O slot may have to be changed in length (the 3x4 RB Auto I repaired O slot had to be shortened by 3/4 inch on the top roller end to work).
The extra length ensures that the curtain will wind to the 1/8 aperture when the curtain is properly tensioned and 1/8 to 3/8 turn of the wind key beyond the 1/8 aperture without stretching the curtain. Excessive surplus can be removed when the aperture slots are cut.
Once you have verified the new curtain to be correct remove it from the camera, cut the aperture slots, install the aperture stays, and reassemble the camera. _________________ The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU. |
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Sirius Glass
Joined: 06 Jun 2010 Posts: 162 Location: Southern California
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Posted: Sun Oct 16, 2011 8:57 pm Post subject: |
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I have a NOS shutter that was installed by Bert. I have patched the shutter for the third time following Bert's instructions. Last night the shutter broke [the third break] while I was testing the shutter after I reduced the tension. I had fired the shutter at all speed several times at tension 1 and just used the 1/8" slot. As I was winding the 1/8" slot up, that slot tore while I was watching.
I patched the shutter today and I would like one or more backups for the time when this shutter needs to be replaced. If I use this shutter for the measurements, doing so will destroy the shutter. I do not want to shorten the life of the shutter.
Steve _________________ Nothing beats a good piece of glass. |
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45PSS
Joined: 28 Sep 2001 Posts: 4081 Location: Mid Peninsula, Ca.
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Posted: Sun Oct 16, 2011 9:21 pm Post subject: |
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What did he make the curtain from?
Check image box squareness with the camera back off.
http://graflex.org/helpboard/viewtopic.php?t=6118
Check curtain to outer camera edge where the back mates distances both sides, left and right.
The revolving back flange protrudes into the camera .040 inch. The aperture stay as it comes over the top guide roller arcs outward then back down. The aperture stays must clear the revolving ring as they go over the guide roller. The 1/8 aperture is the highest on the top roller when the curtain is wound up to that aperture and will be the one most likely to hit the revolving ring. Place the back in the portrait position when checking the clearance. _________________ The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU. |
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