Aperture Blade Repair

[kmac]

I'm repairing two shutters that have the same problem - aperture lock-up.

The first one is a Seikosha MXL off a Konica 111 35mm camera, and the second is an OKK Convex off a DORIS 6x4.5 folder.

In both shutters, an aperture blade was drifting out of position and not all "f" stops could be obtained.

They're a work in progress and I'll deal with the OKK Convex in here before I show the Seikosha MXL.

This thread is also a work in progress, because I won't be able to finish the topic in one go, there's still more to do to the shutters, assembling and testing.

The red arrow points to one blade with a missing bronze spigot, it came loose in the blade and popped out then floated around in the housing and consequently jammed the aperture occasionally.

The bronze spigots are very lightly riveted to the blades in the factory and excess pressure applied to them when operating the camera can work them loose. Grime on the blades can stick them together, causing excess friction when trying  to adjust the aperture.

Edited January 2, 2023 by kmac

[kmac]

I retrieved the loose spigot and cleaned both the blade and spigot ready for gluing using 36 hour Araldite.

You can see the riveted end of the spigot in this photo, and it will push-fit back into the blade and with a tiny bit of Araldite it will be good again after 36 hours (or 24 hours if you're impatient as I am)

As you can see, there's two spigots per blade and they are on opposite sides. One spigot pivots in the aluminium shutter housing, and the other slides in the actuating cam that is rotated when the aperture lever is adjusted to set the aperture "f" stops.

 

Edited January 5, 2023 by kmac

[kmac]

Here you can see the blade turned over and the spigot Araldited back in on the correct side of the blade.

The Araldite was a minuscule amount as you could imagine. I had a tooth pick only wet with the epoxy glue and just touched the blade over the hole where the spigot goes and I lifted the tooth pick straight off without playing around with it any further. Excess glue will jam the aperture up and defeat the purpose of the repair.

The most important part of this job is to have the spigot correctly aligned with the hole before pressing the spigot in. I did this by resting the spigot on the blade, with the glue holding it there, approximately where the spigot goes, then turned the blade over to check the alignment through the hole and made tiny adjustments till it aligned perfectly, then I pushed the spigot in using a plastic drift.

 

 

To be continued

Edited January 2, 2023 by kmac

[kmac]

Twenty four hours later, and the epoxy glue has cured well enough to handle the repaired aperture blade. I can now re-assembled it along with the other blades and test for smooth operation. Assembling the blades proved extremely difficult in their dry state, they kept coming out of place and I found it necessary to lightly grease the blades so they would stick together and stay in place while each blade was located properly before moving on to the next blade, until all were in place. The grease will be washed out using lighter fluid on completion of the assembly.

The next step was to fit the cam plate, which was easy enough, but first the blades needed to be moved using a tooth pick to ensure the bronze spigots that you can see in the photo, would line up with the slots in the cam plate. To keep the cam plate in place, it has two screws that extend through the aluminium body and screw into the aperture lever ring at the rear of the body. These parts together, rotate, and consequently force the blades to open and close.

Testing the aperture revealed a certain grating stickiness. I then guessed correctly that this was due to the cam plate being 180 degrees out of place, meaning the plate, in spite of it's symmetrical appearance, it was in the wrong way. So I carefully removed the cam plate, turned it around 180 degrees, fastened it, after which the aperture worked very smoothly. The final step was to clean the grease out. I did this by flooding the blades several times, mopping up the oily fluid each time.

That completes the repair job, old shutter units need not be discarded, some may be rare like this OKK Convex, and without this one I just repaired, my DORIS folder would be useless.

Hope you enjoyed the topic. I have one more photo tomorrow of the Konica 111 aperture which was exactly the same repair but just a different shutter unit.

Edited January 4, 2023 by kmac

[kmac]

This is the Konica 111 aperture unit. It too had a blade with a missing spigot. I glued the spigot back in using the same two part epoxy glue and 24 hours was allowed to elapse for curing before re-assembly. The re-assembly was easier than the Convex aperture because the Konica has only 5 blades, against the 9 blades of the Convex. An interesting thing about the Konica is that the spigots weren't riveted into the blades, they were just a slight interference fit (light press fit)

All that remains is to finish assembling the shutter units and fit them back on their respective cameras, then go out and take some pics.

To know if a spigot has come adrift in a camera, the aperture lever will come to a solid stop somewhere in it's arch of travel, but the spigot can change position and then the aperture lever will stop solid in another position. A full arch of travel will be very unlikely, spigots are solid pieces of metal and won't "jam", but "block" the rotation of the moving parts.

When I finish working on them, I will to post a pic of the two cameras in question so you can see which ones they are.

Edited January 4, 2023 by kmac

[kmac]

Here are the two cameras ready for picture taking to-morrow. The Doris is somewhat rare, and thankfully everything on this Doris now looks and works great. (The brown on the side strut is only light reflection, the strut is actually nicely chromed). The camera is a simple viewfinder folder, 6x4.5 negatives, has a self timer, a top speed of only 1/200sec, a left-handed shutter button, and flash sync fitting. The aperture repair should hold up for quite a long time, and at the moment it adjusts freely and smoothly.

 

The Konica 111 is a more common camera and there's a YouTube video, over an hour in duration, showing how to CLA the Konica 111A, which is much the same camera but with larger viewfinder.

This Konica is now ready to use with it's repaired aperture working fine also. I bought it at a reasonable price but it was very dry and badly needed cleaning and re-lubricating. There is something strange about these Konicas however, I'll show it in my next post.

 

 

[kmac]

The Konica shutter has six shutter blades where only five will fit. I really have no idea why, but I put it back in on top of the the nearest one you can see there in the shutter. I took an earlier photo while I was disassembling but didn't notice the sixth blade when I dumped the blades onto the work bench. I think it's to take up space, because I noticed that with five blades only, the blades could flop up and down slightly when the shutter was back together, leaving gaps between them allowing light to leak in. I'm only speculating but I think the sixth blade, by taking up space, pushes the other blades flat against one another to keep light out. 

Edited January 10, 2023 by kmac

[Rick_van_Nooij]

Interesting concerning the extra blade. I think your hypothesis is right on why it is there.

Worst thing I've once had to do for a repair was fashion a new shutter blade for an Argus C-2 out of an soda can.  😅

I seriously don't like messing with aperture and shutter blades, though sometimes it's just a necessity to get everything working again.
I had a Franka Solida shutter where there was a very small crack in one of the shutter blades. Another blade had caught on it on the closing stroke of the shutter and jammed the whole thing.

 

[kmac]

20 hours ago, Rick_van_Nooij said:

Interesting concerning the extra blade. I think your hypothesis is right on why it is there.

The guy in the YouTube CLA video left the sixth blade out intentionally without an explanation as to why he did that. I was thinking that there must be a reason, so I did the wise thing and placed it back in the shutter. If it was good enough for Konica to have it there, then I won't question Konica's technical research and expertise.

 

20 hours ago, Rick_van_Nooij said:

I seriously don't like messing with aperture and shutter blades, though sometimes it's just a necessity to get everything working again.

I know what you mean. Most of the time I will give them a good clean if a clean is all they need, and they are not catching or jamming. Otherwise I force myself to strip them down and see what the problem is, and it's also an opportunity to very lightly lubricate the pins, pin holes and spigots. ( A subject for another thread)

I took the Doris out for a test run the day after I finished it and it worked superbly. I used a Hanimex accessory rangefinder for focusing, cheap, but it is very contrasty and has dual indexes, imperial and metric, the Doris needed metric, plus both planes can be adjusted externally. It's just a pity it won't fit in the cold shoe, the shoe on the Doris is narrower than more modern shoes by about 1.5mm

Handheld, the Doris proved to be very steady because the shutter release button is soft and smooth to press. I'm worried about light leaks though, if there are any, it'll be back to the work bench. I'll finish exposing the film today and we'll see how it is after development.

Edited January 13, 2023 by kmac

[chuck_foreman1]

Very impressed withe hands-on shutter talk here.. I would also not mess with leaving something out... but I doubt I would try to fix something on this lever ..well maybe ..try  🙂

 

[kmac]

On 1/16/2023 at 12:53 AM, chuck_foreman1 said:

Very impressed withe hands-on shutter talk here.. I would also not mess with leaving something out... but I doubt I would try to fix something on this lever ..well maybe ..try  🙂

 

It requires courage to do your first shutter, after that they get easier. Losing springs and small screws is the big worry, I have a pole magnet I slide across the floor to pick up anything that might be down there. Small brass screws and objects need a strong torch light to find them.

I finished the Konica, that is, I thought I'd finished it, I was trying out the aperture and shutter, and the "B" wasn't working. Off the shutter came again only to find a hair like spring was out of place, only needed flipping back onto the lever it was meant to be on, phew! The whole camera is now working great thank heavens. 

I developed my first film from the Doris, but something about my developing was not right, old developer I think. Every shot looked underexposed, I had to do some adjusting. Nice sharp lens in that little old folder, it's a bit sharper than you see here on PN. I'm happy with the aperture, it's working great. 

Film Ilford Delta 100, ID 11 1:1 10.5mins 20C

Rotunda

 

Childrens' thingamajig

 

Piggy the mail box

[Alun Thomas]

Interesting thread, I decided a couple of days ago to open and clean a very old Tokina 300mm F/5.5 lens which had several blades out of place. Unfortunately when I finally worked out how to get to the aperture mechanism, 3 of 18 blades had the same problem as you found. But, fortunately, the 3 small metal spigots were all able to be found in the mechanism, a small miracle in itself. I glued them back into place, quite tricky work if your eyesight is starting to give. Then there was all the fun of reassembling 18 blades, luckily the aperture is one that can be completely removed from the barrel, assembled, the top locating plate put in place, then dropped back into the barrel all in one piece.

I was slightly apprehensive (even though it's only a ten dollar lens) that the glue might not hold, however the aperture mechanism is now as smooth as the proverbial babies bottom. The lens itself is reasonable but not exceptional, with a 4 element 2 group arrangement, a double at the front and another at the rear of the lens.

[kmac]

Excellent job Alun, I idolize you for tackling that one, with how many blades ?, looks like about twenty. Exercise them often over the next week to check for tight spots, but if the glue was left to set long enough before assembly, the aperture should be fine.

[Rick_van_Nooij]

My most recent reseating adventure on a Compur-S shutter from a Zeiss Super Ikonta.
Couple of the blades had knicks in them from having come unseated and someone forcing the aperture ring.
I had to flatten those out and rearrange them so they would not catch on each other again.

The blades were also very greasy....possibly someone squirting in some WD40.

The shutter and camera had a few other issues too, but those are now cleared up and it can go back to its owner somewhere in the next month (once I finish all the other Super Ikontas he's given me to service)

Edited January 17, 2023 by Rick_van_Nooij
typos, grammar