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Graphic Roll Film Holder update

 
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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Thu Oct 04, 2012 7:59 pm    Post subject: Graphic Roll Film Holder update Reply with quote

I am routinely updating these posts as I develop more information.
Photos from this post are now in a private album on my flickr.
Guest link: https://www.flickr.com/gp/thirteenthumbs/s4V2zZ/

For several years I have been recommending adding a .010 shim to the pressure plate of the rfh to improve film flatness and close focusing issues.
Doing this may increase the force necessary to advance the film and may cause the wind key to strip. The wind key is the soft metal, possibly lead as it will melt as easily as solder, part that mounts on the bottom of the advance shaft and mates into the take up roller.

I have a Graphic 22 and 23 in 4x5 and recently acquired a 22 in 2x3 and a RH10 insert.

The 22 in 4x5 has always had issues with film flatness and close focus issues. Adding the .010 shim to the pressure plate cured the flatness and focus issues but created drag which stripped the wind key.

Large format film holder specifications state the film plane to be .197 inches below the holder edge .007 for formats 2x3 through 4x5. .007 is the film thickness of TriX320 in 4x5 format.

Checking the rfh I have on hand I found that any of the 4 inserts pressure plate in the 2x3 frame were .197 from the camera side surface; in the 23 4x5 frame they are .203, and in the 22 4x5 frame they are .214.

Now roll film from Kodak and Ilford is .004 (4 mil ) to .0045 (4.5 mil ) while Fuji is .0035 ( 3.5 mil ) so I assume that the film plane in a rfh should be within the film thickness either side of the .197 film plane holder depth.

On all 3 rfh frames there are two machined in guide rails top and two bottom that the pressure plate rests against when the insert is in the frame. On the 2x3 frame and the 23 4x5 frame both rails have a height of approximately .031 inch. On the 22 4x5 frame the outermost rails are .046 while the inner ones are .031, an .015 difference.

An easy way to check the rail height is to use a precision ruler marked in fine graduations and measure along the length of the rail to the base of the rfh. 1/32=.031


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Last edited by 45PSS on Thu May 15, 2014 1:49 am; edited 2 times in total
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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Mon Oct 08, 2012 11:16 pm    Post subject: Reply with quote

I ground the outside guide rail to closely match the inside rail with a Dremel and 60 grit sanding drum.

Kodak and Ilford backing paper for current B&W films is .004 thick.

Wind knob 4-40 left hand thread.

Wind key thread is 3-56 left hand.
EDIT


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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Wed Oct 10, 2012 11:39 pm    Post subject: Reply with quote

If the lockout lever has to be held to advance film to the next frame then the lockout spring has broken. It is riveted to the lockout lever. The spring is .006 inch thick. The spring at point D is approximately 5/64 inch wide. All images were made from a fixed camera position so it should be easy to copy/enlarge/print to actual size.


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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Wed Oct 17, 2012 10:12 pm    Post subject: Reply with quote



To remove the top cover from a Graphic 22 or 23:
1. Holding wind pinion E stationary turn the wind knob clockwise (opposite direction of arrow) and unscrew from the pinion.
2. Unscrew screw D enough for frame number dial to turn freely. Put a piece of tape over screw D to prevent it from falling out. Unscrew frame number dial.
3. Remove screws A, B, and C.
4. Lift top cover at pressure plate side and slide off lockout lever then lift off the insert.
Reassembly:
Screws A are self taping and will retap the holes if not started into the original threads.
1. Slip top over lockout lever and into position on top of insert.
2. Start screws A, B, C and leave 2 turns loose.
3. Lay insert pressure plate down, top to your left on a clean, flat, smooth surface.
|4. Place a .0001-.00015 feeler gauge between the cover lip and the work surface and push cover snug against the gauge then tighten the screw nearest that corner.
(4a. RH20 instructions: lay insert on a flat surface with the top to the left. Place left thumb on center support bar and index finger under lower cover corner that is away from you. Pull up and back then snug screw A to hold position. Push down on corner near you and snug screw A near you. Tighten all screws.)
|5. Repeat for all corners.
6. Tighten screws A, B, C.
7. Thread frame number wheel onto screw D and seat on cam in the same index position as it was before removal. Tighten screw D. Over tightening screw D will break the frame number wheel.
8. Install wind knob on pinion by turning it counterclockwise (with wind arrow) until tight.

The instructions from the RH20 were originally posted and they resulted in too high film advance tension. | indicates steps changed.

Cover Removed



1. pinion, film advance
2. plate assembly, bearing
3. ratchet-lock
4. spring, ratchet lock stop paw
5. spacer
6. gear, intermediate
7. pinion, intermediate
8. lever assembly, lock
9. screw, cam bearing
10. cam
11. gear, cam
12. lever, counter engaging
13. spring, engaging lever
14. bearing, engaging lever with spacer
15. ratchet lock stop paw
16. spring, lever assembly lock
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Last edited by 45PSS on Sat Oct 27, 2012 8:29 pm; edited 3 times in total
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45PSS



Joined: 28 Sep 2001
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Location: Mid Peninsula, Ca.

PostPosted: Fri Oct 19, 2012 11:29 pm    Post subject: Reply with quote

Spacing issues


On Graphic 22 inserts the pressure plate over lays the supply and take up rollers with a .005 inch gap between the roller and pressure plate end.
Pull outward on the pressure plate ends until the gap is .020 inch at each roller. The gap must be even along the roller.

The two Graphic 22 inserts I have measure as follows:
Pressure plate length - 3.76 and 3.78, edge to edge at center
Supply roller - .434 and .432, possible production difference.
Take up roller - .434 and .433, possible production difference.
Supply roller outside edge to take up roller outside edge at center pressure plate side 3.966

Graphic 23 measurements:
Pressure plate 2.927 inch
Supply roller .620 inch
Take up roller .429 inch
Supply to take up outside edge at center of pressure plate 3.82 inch.

RH10 measurements:
Pressure plate 2.925 inch
Supply roller .620 inch
Take up roller .45 inch
Supply to take up outside edge at pressure plate center 3.834

For spacing issues on the Graphic 23, RH10, RH8 attach .012 inch to .016 inch shim ( 3 to 4 layers of backing paper, 2 layers shutter curtain material that is .008 inch thick) to the take up roller. RH12 should be similar to Graphic 22.
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Last edited by 45PSS on Tue Oct 23, 2012 4:12 am; edited 1 time in total
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Henry



Joined: 09 May 2001
Posts: 1439
Location: Allentown, Pennsylvania

PostPosted: Sat Oct 20, 2012 2:43 pm    Post subject: Reply with quote

While I've never had a problem with film flatness in my RFHs for the Century Graphic (3 6x7 RH10s, an RH20, and a 6x9), I did have a very annoying problem with one of the RH10s: the advance lever was extremely stiff, so much so that I feared damaging or even snapping it off. Looking into the case, I noticed the small washer under the winding key (at "E" in your photo above), and decided to see what effect removing it would have. Result: it cured the problem! The mechanism works fine without the washer, and I've left it off permanently. This must be a sample defect, because the problem doesn't arise with my other holders.
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Dan Fromm



Joined: 14 May 2001
Posts: 1883
Location: New Jersey

PostPosted: Sat Oct 20, 2012 7:45 pm    Post subject: Reply with quote

Charles, your comment

Quote:
For spacing issues on the Graphic 23, RH10, RH8 I suggest attaching a piece of film to the supply and take up rollers effectively increasing their diameters by .004 inch, RH12 should be similar to Graphic 22.


caught my eye. So I asked an RH-12 and a "23" whether their rollers were connected to the frame counter/auto stop mechanism. Since both rollers spin freely, I don't think they are. I'd always thought that the frame counter/auto stop mechanism was geared to the advance lever (or knob). And I do know that my SubSea/Graflex RH8 that overlapped frames badly turned out to have RH10 gearing. Just another manufacturing defect from SubSea.

Anyway, what have I missed?
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45PSS



Joined: 28 Sep 2001
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PostPosted: Sat Oct 20, 2012 9:02 pm    Post subject: Reply with quote

Henry,
Its possible someone put a washer under the wind key that is too thick.
The only service instructions I have are for the RH20 and a few service bulletins. The wind key washer is listed as 0.312 x 0.128 x 0.010 . The instructions state to check the washer is on the shoulder of the pinion and not clamped by the wind key. It is brass so it will act as a bushing.

Dan,
The insert is a single piece of stamped sheet metal. The lower film spool spring is riveted into the insert and the center support bar bradded into the insert. The supply and take up rollers are removed / inserted by spreading the ends of the insert equally to prevent distorting the insert and slipping them out or in. The take up has a spacer at each end that is larger than the roller and act as film centering guides.

The wind knob or lever is on a geared pinion, knob/lever on one end, wind key on the other. Next to it is a shorter pinion with intermediate gear and frame lock lever. Next is the frame counter drive gear, cam, and dial all held in place by the dial screw. Film advance is by action of the wind knob or lever only. Film spacing is determined by the frame cam and distance the film must travel from supply to take up.

The distance between the notches in the frame cam vary from the start of a roll to the end, wider at the beginning, narrower at the end.
Film thickness has changed over the years and the cam was cut for the thickness in production at the time. The only remedy we have today is to machine a new cam with the frame notches repositioned for current film thickness or increase the distance the film must travel from supply to take up using the existing cam.
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Dan Fromm



Joined: 14 May 2001
Posts: 1883
Location: New Jersey

PostPosted: Sun Oct 21, 2012 3:27 pm    Post subject: Reply with quote

Charles, you wrote:

Quote:
The wind knob or lever is on a geared pinion, knob/lever on one end, wind key on the other. Next to it is a shorter pinion with intermediate gear and frame lock lever. Next is the frame counter drive gear, cam, and dial all held in place by the dial screw. Film advance is by action of the wind knob or lever only. Film spacing is determined by the frame cam and distance the film must travel from supply to take up.

The distance between the notches in the frame cam vary from the start of a roll to the end, wider at the beginning, narrower at the end.


I'm sorry, but I still don't get it. Graflex' roll holders count turns of the take up spool, not turns of the rollers at the gate's ends. The cam adjusts the number of turns/frame according to how full the take up spool is. That's why we have to load the film with the "ready" mark on the backing paper matching the arrow on the feed side of the insert. And that's why frame spacing is sensitive to film thickness.

Your advice on changing the feed side roller's thickness to adjust frame spacing is correct for the AAR 620. There the feed side roller has a cam that whacks a push rod that works the frame counter ratchet. Larger roller, fewer whacks/inch of film, tighter frame spacing.
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Henry



Joined: 09 May 2001
Posts: 1439
Location: Allentown, Pennsylvania

PostPosted: Mon Oct 22, 2012 6:48 pm    Post subject: Reply with quote

45PSS wrote:
Henry,
Its possible someone put a washer under the wind key that is too thick.
The only service instructions I have are for the RH20 and a few service bulletins. The wind key washer is listed as 0.312 x 0.128 x 0.010 . The instructions state to check the washer is on the shoulder of the pinion and not clamped by the wind key. It is brass so it will act as a bushing.


I checked the washer and its position relative to pinion and key, and both seemed to be in order. But no matter, the main thing is that the mechanism functions fine without the washer, so it's outta there. I'm just glad the solution was so simple!
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45PSS



Joined: 28 Sep 2001
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Location: Mid Peninsula, Ca.

PostPosted: Tue Oct 23, 2012 4:45 am    Post subject: Reply with quote

Quote:
I'm sorry, but I still don't get it. Graflex' roll holders count turns of the take up spool, not turns of the rollers at the gate's ends. The cam adjusts the number of turns/frame according to how full the take up spool is. That's why we have to load the film with the "ready" mark on the backing paper matching the arrow on the feed side of the insert. And that's why frame spacing is sensitive to film thickness.


The only variable we can change easily is the distance the film must travel from the supply side to the take up side. By increasing this distance by .015 to .020 inch causes the same amount of film being wound to have to move farther when crossing the film gate area.

I tried adding .004 inch to each the supply and take up rollers. This gave a 3/64 (roughly) difference in spacing and a slight increase in wind tension. I removed these and attached a double layer of .008 shutter curtain material to the take up roller which on average is .019 inch smaller in diameter than the supply roller.
Using a processed roll of Delta 100 uncut reattached to the backing paper as it was from the factory and running it through a Graphic 23 that had uneven spacing between frames but no overlapping I got these results:
No roller change, .008 inch total change // .016 inch to take up roller only
Edge to end of frame 1 - 5 18/32 inch // 5 12/32 (3/8 )
end of 1 to end of 2 - 3 14/32 // 3 20/32 (5/8 )
end of 2 to end of 3 - 3 22/32 // 3 20/32 (5/8 )
end of 3 to end of 4 - 3 20/32 // 3 21/32
end of 4 to end of 5 - 3 23/32 // 3 20/32 (5/8 )
end of 5 to end of 6 - 3 19/32 // 3 20/32 (5/8 )
end of 6 to end of 7 - 3 19/32 // 3 20/32 (5/8 )
end of 7 to end of 8 - 3 18/32 // 3 16/32

Frame length is constant. Distance between frames 8/32 - 9/32 with modified take up roller.
1/32=.03125 = 0.79375 mm
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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Tue Oct 23, 2012 5:33 am    Post subject: Reply with quote

Take up spool turns (watch dial attached to empty spool, turns counted, 1 minute=6):
Graphic 22 || Graphic 23 || RH10
Start to 1- 8 turns +198 or 3078 || 8 turns +240 or 3120 || 8 turns +246 or 3126
1-2 462 (1t+102) || 708 (1t+348) || 588 (1t+228)
2-3 480 (1t+120) || 672 (1t+312) || 588 (1t+228)
3-4 438 (1t+ 78) || 624 (1t+264) || 552 (1t+192)
4-5 450 (1t+ 90) || 600 (1t+240) || 528 (1t+168)
5-6 438 (1t+ 78) || 552 (1t+192) || 498 (1t+138)
6-7 414 (1t+ 54) || 540 (1t+180) || 492 (1t+132)
7-8 402 (1t+ 42) || 516 (1t+156) || 468 (1t+108)
8-9 378 (1t+ 18) || not used || 450 (1t+ 90)
9-10 372 (1t+ 12) || not used || 438 (1t+ 78)
10-11 378 (1t+18)
11-12 348 (87/90t)
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45PSS



Joined: 28 Sep 2001
Posts: 3208
Location: Mid Peninsula, Ca.

PostPosted: Tue Apr 15, 2014 3:57 am    Post subject: Reply with quote

I have further researched the spacing problem on Graflex Corp. roll film holders. I have one from 1949 that is original to a 1949 RB Series B that was worn out by a professional photographer. No amount of tweaking would get it to quit overlapping images. The techniques previously discussed in this thread helped minimize the overlapping but would not eliminate it.

The main cam has gaps in it corresponding to the number of frames the roll holder was made for. Each gap, where the lock lever engages, should be .55 inch. The worn out holder that would not quit overlapping cam gaps are .56 to .58 inch. A feeler gauge should sit .001 to .005 into the gap.


Film is drying on a holder that its cam measured .55 to .56. Spacing is 1.5mm to 2.5 mm except frame 1-2 which is .5mm on a 12 exposure roll. The frames where the cam gap is .56 are the closest, the ones with the cam gap measuring .55 are the furthest apart.
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