Project 9, repairing the Agilux Agiflex I

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When it arrived in early 2020 the Agiflex I was cosmetically tolerable but exhibiting no intention of working. Every control was stiff or seized solid and it was generally fairly grubby. The hatch catch was seized shut, the focus and aperture controls stiff and the wind on mechanism solid. Advancing the shutter using a 270º clockwise twist of the shutter setting wheel, produced movement, albeit it very gritty and stiff. On releasing the shutter, an apologetic "swish" was heard, but clearly all was not well. The good news was that the, often troublesome, cable was clearly intact and still on the pulleys. There was no evidence of tampering and so was likely to be as it left the factory inside.

It entered the workshop on 7th August 2020.

As the lens was very dirty I elected to start there, there being little point in expending too much effort if the lens was beyond saving. The lens barrel comes apart from the front, using no special tools other than a lens wrench. The construction is logical and it's difficult to set it up incorrectly, just make a note of where the focus barrel leaves it's multi helical thread to make things easier. Clean everything, there are several wide mating faces - dirt and light surface corrosion on these stiffens the whole thing up appreciably. The aperture leaves are operated by a cylinder that continues to the back where they are nested. I didn't need to take the leaves out as everything freed up very nicely once cleaned, and it looked a tricky job, so I passed on that. The focus is set up deliberately stiffer than the aperture control, a curved copper plate spring serving as a brake. The reason is to prevent the focus from changing when the aperture is manually set just prior to taking the image. A cigarette paper inserted as a temporary shim between the focus and aperture rings when you tighten up the latter will prevent too tight a fitting between these controls.

The lens elements and barrel cleaned up well enough to move onto the camera, one motive being to establish the truth of the oft repeated claim that the Agiflex is a copy of a Reflex Korelle.

To get the hatch off the catch screws needed to be removed. This revealed the catch slide which was a little corroded hence sticking. It was a very poorly made strip of metal with clear hand filing, but the zinc electro plating suggested it was an original part. With the hatch off it wasn't clear what order the thing should be taken apart. The nuts holding on the focal plane plate are a deviation from the Korelle with no way to put the screws in from the other side, the obvious conclusion is that the nuts must come off later. Since the shutter was showing no signs of working and was now seen to be full of holes and cracked, it rather looked like it would need a new set of curtains even at this early stage. So I elected to remove the focal plane plate nuts and wiggle the screws out anyway so I could see things clearly. This gave me the opportunity to record the undisturbed capped position of the curtains you see here. The rear (first) curtain stops with its capping strip only just short of the guide roller. Any further than this and it will start to cant up, possibly preventing the second curtain from capping. This is the sort of important information that must be gathered during a strip down.

With the crank handle removed, the first evidence of a previous trip to the repair shop was revealed with a tiny V mark aligned with the crank stop. The three screws on the surround screw into pillars mounted on the shutter box plate ends below. Technically, there is no need to remove the top plate to gain access to the shutter though, but since the whole camera was going to get a thorough deep clean, it was taken off anyway. There are two further screws hidden beneath the leatherette along the back top edge aligned with the mirror box. These hold the back down tight in this region but also secure a shim to give the tensioning cable some space. Removal of the top plate gives access to the shutter timing gears and removes the entire wire tensioning system.

On the right hand side is the housing that contains the tensioning cable spring. The job of the spring is to maintain tension in the cable so it doesn't come off the pulley and supply the drive to return the rewind lever at the end of its stroke. It's pre tensioned 120º, so keep this in mind. There's no pressing need to take the spring housing off though, unless you like taking springs apart. Clearly I do, as it was removed, de-gunked, polished and re-installed with a film of lithium grease. The drive is transmitted to the shutter via a peg, so the slot for the inner spring anchor is used to back off the pulley slightly to make sure the peg aligns with its compatriot on top of the first curtain shutter wheel when it all goes back together. Hidden under the leatherette are three further screws that go into three pillars as per the other side, holding the top down. The shutter indicator plate has been removed in this image.

An example of scribbled notes as things are taken to bits, down to which screws came out of which hole. Handy in this case, as one screw refused to go in any hole except the one it came out of, despite being apparently the same. oddly, there are as many typos in my hand scribblings as on here... I do know how to spell 'rotate', honestly.

These notes are important as occasionally a camera can spend a few weeks in bits whilst parts are sourced or made, and my memory can let me down these days. It took me ten days to source the correct gauge spring steel for the sprung shutter roller anchors for this camera.

With the top plate removed, which isn't actually necessary, it becomes apparent that the two large nuts surrounding the film spool pintles in the film chambers are what hold this thing together. Everything was photographed to record its position before disturbing it further. The mirror was removed to prevent nasty accidents early in the strip down. It's a particularly fiddly task with tiny non-captive screws and nuts. Clearly betraying it's parenthood, as this is the sort of construction used in many an aircraft instrument, AGI's primary business. At a casual glance it's very similar to a Reflex Korelle... but is it a copy?

Korelle (B) on the left, Agiflex on the right. Whilst the broad theory is adopted, the Agiflex differs in almost every detailed respect. The gear ratio is maintained although the pitch is different at 11/45 and 12/49 respectively. The travel angle is identical at 270º and both shutter rollers rotate three full rotations during their travel. Construction differs totally as does the position of the stop bar. The Korelle is also rather better made...

The Agiflex gears are chemically blacked steel, but have rusted, with surface rust wherever the coating has been abraded during use. The Korelle gears are nickel plated brass.

This serves to illustrate how the Agiflex shutter mechanism lifts out from the cast body.

I had to make a spanner by modifying a circular saw blade spanner for the two large nuts, an awkward 13.2mm across flats. Once they are removed, pressure on the film spool pintles will start to move the entire shutter assembly up and out of the body. Ordinarily the focal plane plate remains in place, but it's removed here for clarity and must be installed prior to lowering the shutter assembly back in later, as there is no other way to do it. It's very tight and best practice is to partially advance the shutter until the capping strips are halfway across the film plane, press lightly on them near the top, this will prevent the capping strip from getting caught on the way up. Once clear of the lip, the shutter assembly readily moves. Don't be tempted to use the end plates to pull the shutter out, it's better to get your thumbs under the base plate as soon as there is a bit of space, as this prevents the end plates from bending.

This method of construction is utterly different to the Korelle, whose shutter is assembled in situ. The function is very similar though. This choice of assembly does make the Agiflex very prone to rubbing and there is evidence on this example to show this from new. Like the Korelle, the second curtain has to pass over two 90º bends. This adds considerable drag to the shutter. Add to that a shutter that has deteriorated whilst parked in one position for decades and you have the recipe for a dead shutter. This is what befell serial 1813, a very early production example - and one worth saving.

The one piece die cast aluminum shell of the Agiflex is executed well, but even so the mould lines are clearly visible and no one at Agilux thought it was worth their time to grind them off and polish to an agreeable finish. Tut tut.

It bears no resemblance to a Korelle casting other than the process used and broadly similar shape. The roller chambers are formed partly by the casting and partly by the folded steel assembly that lowers into the casting as a pre assembled unit, this is preferable and similar to Exakta practice. But Exakta did it much, much better.

With the casting set free of it's pesky mechanicals it can be given the first decent clean since it left the factory. There was no need to disturb the shutter trigger mechanism, it was all working smoothly and could be cleaned in situ.

There is a piece of lightproof cloth that seals the hinge line of the mirror hinge. This had cracked and would allow light from the viewing hood to strike the film during exposure. A piece of new shutter cloth was cut to size to replace this.

Once removed from the body the shutter can be worked on as a working sub assembly, but only so far as to get it functioning. It behaves completely differently out of the shell than in it. With the first curtain wheel removed the second curtain takes up the slack left by the missing first curtain pin. Visible here as the second curtain capping position is further to the left compared to the earlier image before anything was disturbed.

The space allowed is very tight, there is only just enough space between the spring powered curtain spools to clear each other when released. Insufficient initial tension in either allows the curtains to bulk up fractionally, causing them to rub at the beginning of the cocking sequence. One tooth out on the second curtain does the same. The entire shutter also sits in the shell at a slight angle.

There was no evidence of tampering discovered, but a couple of oddities did show up. The screw holding the 2nd curtain timing end spool to its spindle was not flush into its recess, although it was tight. This had damaged the shutter cloth and caused a bulge with each rotation, effectively increasing the spool diameter at the top. The cloth was also initially glued further around the roller and was changed later. The change is very old, possibly during manufacture.

Towards the right of the image you can see the witness mark and the "memory" bend left by the first tight guide roller, as well as the cracking in the failed light proofing. Both curtains were well beyond saving and would need replacing.

The second curtain after removal. Apart from being more like stiff paper, the memory from being stored for many years was causing unacceptable break out loads that would put severe strain on the four strand wire rope that acts as the shutter tensioning transmission.

This closer in view shows the memory bend more clearly and the original position of the curtain as glued to the roller, its light proof backing was left behind when repositioned at some point in the past. There are also two parallel witness marks running the length of the curtain. These were caused by the heads of the screws holding the film brake springs protruding too far into the curtain cavity causing them to rub against it every time it was fired. Just one of many areas the Agiflex picks up pointless drag. In the name of originality I didn't alter this when putting it back together, as this was relatively minor, given some of its other draggy features.

The first curtain had been parked fired for many years, hence wound around its own spring roller tightly. Having grown accustomed to this position, it protested at being unwound and cracked for its entire length resulting in these tell tale wrinkles and myriad pinholes. No further use except as a pattern.

The standard of workmanship on this early production Agiflex is poor, roughly filed and hand sawn components abound with absolutely no effort expended to finish anything not visible, or even visible in some cases. These rough saw cuts allow the base plate to be flexed enough to install the guide rollers. The folded steel box is actually impossible to fold from one piece, a convenient blob of weld fills in a gap and is then fairly crudely ground back, resulting in the suspicious thinning of the metal just left of centre. The assembly is electro zinc plated and hand daubed with thick matt black paint using (maybe) a used tea bag or a floor cloth. Ah, the state of manufacturing in post war austerity Britain.

The top plate revealed after the shutter timing wheels and trigger levers were removed. It was hewn from the earth around AD1946 by some Neanderthal in Croydon using a flint axe.

Believe it or not, this shows it after a thorough clean.

This number, hand etched with two passes of a rotary etcher, is contemporary with manufacture. The crystalline oxidation structure on the surface matches areas that were not plated thoroughly. It would be interesting to know if anyone else has similarly marked examples. Prod the little symbol in the middle of the foyer to drop me a line, if you have something similar.

The speed selector components follow Korelle practice, but are not compatible in any way. This image shows them after a thorough clean, de-burr and polish. Ready to go back in. That split pin is a fiddly little blighter, I'll have you know.

cleaning the shutter curtain rollers of the Agiflex

Meanwhile the messy job of scraping off the old curtain cement to re-use all the metal components of the shutter curtains. The curtains are glued on tight to the bottom, leaving the clear area near the top where the curtains don't reach the top. This is important to prevent rubbing. Well, it rubs anyway... but at least it's manageable in this position.

The home made curtain jig allows the rollers to be positioned square to the cloth, whilst the depth screw sets the vertical position to make sure all four rollers are consistent. The curtains on the Agiflex need to be set right at the bottom of the rollers, else the second curtain's top edge will bind as is scrapes along the focal plane window in the main shell casing. The tolerance is so fine that an eighth of a turn on the main mounting nuts is the difference between it rubbing or not. Given that the currently available silk backed shutter cloth is considerably stronger than the original linen, it would be possible to shorten the height of both curtains by 1mm, adding 0.5mm clearance top and bottom would avoid one of the Agiflexes drag issues. The new curtains were made to the original specification though,

As I have previously done, I made new brass capping strips and fitted them. They survived about four test releases before falling to pieces. So I took the curtains out, went up a gauge on the brass strip and tried again... they survived a little longer, just long enough to get the whole thing re-assembled before they too gave up the ghost. At which point I salvaged the original steel capping strips from the old curtains and crimped (with a bead of cyano for good measure) them in place. Here a card set square is being used to make sure the capping strips are still square after all the shenanigans. Then it was all assembled again. Sigh.

The cable tensioning system is composed of a four strand wire rope made from a fairly mild and ductile steel. Care needs to be taken as it can bend quite readily. One end is soldered into the pulley, whilst the other end splits into two strands and is anchored around a screw. The pulleys are chrome plated over brass and the chrome plate was peeling off one, causing it to jam. The plating was removed where it interfered with the shutter setting pin.

There was no need to disturb the wire to clean everything and it went back together without any trouble. The cable is prevented from coming off the pulleys by keeping it straight and 120º of pre tension in the spring mechanism.

The cable only serves to cock the shutter, film transport is direct drive from the advance lever. Intentional double exposures can be made by cocking the shutter by rotating the speed selector clockwise.

5th September 2020.

Et Voila! Am I going to recount in great detail the tribulations of getting the thing back together? Well - as the great Haynes manual always said "reassembly, is the reverse of disassembly".

The shutter box needs to be fully installed and the nuts tightened before you can start adjusting the shutter timing and benefits from several test releases before it settles down. To set the timing I adjusted each spring roller until it had just sufficient torque to pull its curtain over to the capped position, this establishes the base setting to overcome the static friction in that curtain, as both are very different, and every camera will be different. Then I set the ramp up and travel time for each curtain, which needs to be around 0.05sec. Assuming all is well with that, the duration at 1/25 ought to be around 0.04sec and the other speeds should fall in line closely enough for my purposes. How I do this isn't actually a secret, but I am sufficiently embarrassed by my method as to avoid ridicule, but one day who knows... this is project page nine. Maybe a confession is a long time coming for Project page ten.

Next restoration Project page.