Deep cleaning the Robot II

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Project 8, Deep cleaning the Robot II

The Robot II is a well made and reasonably desirable 35mm film camera dating from the late 1930s. The characteristic that makes it stand out from the crowd is the clockwork mechanism that advances the film after each picture is taken, which in practiced hands could enable 4 frames per second to be exposed.

As asking prices are usually higher than I am prepared to pay, I was happy to take a chance on this snotty looking wreck. Here it is straight after it was delivered. There's not much good news, other than there being nothing missing and it was making weak efforts to work. It had clearly been left out in the open, probably an attic where it had been alternately baked in summer and allowed to get damp in winter, such is the fate of objects entrusted to British attics. The first impression was that the covering was beyond saving, and there was a lot of rust. The state of the lens, wasn't looking encouraging.

Underneath the filth, can be see extensive wear to the chrome plating, suggesting that this camera had seen a good deal of use back in its day. The faux leather covering really was too far gone, it's a plasticized coating onto a linen base, but it had gone stiff and also reacted with some contact adhesive used by some previous owner to try and stick it down. The metal Robot badge on the back is heavily corroded, pitted and going to be a challenge to make presentable. It fell off shortly after this picture was taken.

The story doesn't improve from the top. Five different drivers are used to get the top housing off, clearly Berning had no interest in standardizing fixing types. The tolerance on the top housing proved to be very impressive, the hole through which the main spring barrel protrudes as an exact fit, and the housing needs to be released patiently by easing up each end, front and back gently from the tray it sits over. The main spring knob is simply removed by turning it backwards, it's best to ensure the main spring has released to the end of it's travel before doing this.

It actually looks reasonably clean on the front face of the shutter, albeit with some mould growing in there.

Well, I've seen worse. And quite a lot better too. The B in front of the serial confirms this to be a Robot II. The very filthy, to the point of being opaque, lens has a serial that dates it between 1943 and 1944. During WW2, Robot II production continued for the military, generally painted black in place of chrome and often with rather ugly taller spring cases and winders, holding longer springs. It's conceivable that the lens was made for a military contract but never used and was subsequently used post war for this civilian version when production started again.

The Robot specific 'T' supply spool and 'N' take up spool sit in the recesses either side. In use the film travels from the left to be deposited in the right side. Unlike Kodak 135 35mm canisters, the Robot ones are made so that they open the felt light trap as the back closes, this task effected by two pegs strategically positioned and riveted into the rear hatch. Opening the felt light traps reduces the chances of scratching the film and eases the drag in the system, giving the spring a fighting chance, even though it is quite powerful. The canisters should, accordingly, be cleaned and kept smooth running too.

Once the top housing was teased off it was apparent the dirt had found its way in here too. Given the tight fitting this was surprising. However there are no window coverings, the counter window and shutter lock slider are open to the air. The original 70 year old grease has prevented the sprocket on top of the spring housing from rusting too much, though there was a hint. Mostly just dirt, nothing too tricky here. In the middle of the film counter disc can be see the topmost wire of the spring clutch that transmits drive to the take up spool. Most of these gears just rest on their spindles and can be lifted off. Getting the top housing back on is a bit fiddly, as the counter wheel and thumb wheel reset need to be held inside the housing as it's lowered back down. The button and spring for the counter disengage, needs to be held down too, and a cutout for a brass strip is let into the front for this purpose.

With the top gear train, viewing optics removed and the main spring withdrawn, the shutter and clockwork gear train can be removed in one piece and separated into their separate mechanisms. It's here the simplicity and accuracy of the design starts to make itself apparent. That hole for the main spring aligns perfectly with the chassis beneath and in turn the top housing, the tolerance wouldn't allow a cigarette paper in between. Given that it's a mixture of machined brass plate, stamped and spot welded steel case and pressed brass housing, it's an impressive feat.

With all it's internals removed, the Robot's fascinating naked shell is revealed. What initially looked to be rust was decayed glue, both the original and subsequent efforts to stick the covering back on. I had read that the shell was at least partially made of stainless steel and I was keen to investigate this, as it's an unusual material too use in camera manufacture. Stainless steels are generally made by mixing chromium with steel to make it all but immune from corrosion. This can make it hard and brittle though. A high chromium content makes the material non magnetic. The shells on this Robot II show no sign of rust pitting, even when the screws let into it had all but rusted to powder. Clearly since the part of the shell adjacent to the screw had been subjected to the same conditions, the shell is certainly rust resistant. Under the microscope, there is no pitting at all, yet the material is magnetic. So the camera shells are pressed from a relatively low chromium stainless steel, a material that is both corrosion resistant yet sufficiently ductile to be formed in a press. These front and back panels are spot welded onto the top and base plates of a similar material. However, they are relatively thin, so to add rigidity to the lens mount a fairly thick stainless panel is spot welded to the front. The tell tale weld dimples clearly betray this. You can see that the rear hatch is finished in black wrinkle paint, the rest of the camera was painted satin black internally. Various other components are either riveted through the shell or spot welded. Many processes, finishes and materials made up the shell alone, Heinz Kilfitt - the designer, seems to have wanted to use every toy in the manufacturing toy box. Hardly surprising that Eastman Kodak declined to take the design on.

This shows the shells after they were cleaned up and ready for the new covering. For ease I just used my regular semi coarse Morocco pattern goat leather, as it's the correct thickness, even if the pattern is coarser than the original.

This is the delightfully simple, mainly brass, mechanism that transfers the torque from the spring to the sprocket wheel and take up spool, with the main spring removed. To the right of this image is the rusty governor mechanism, which wasn't helping the camera at all. These gears are steel stampings. Unseen to all but the most dedicated dismantlers is the serial number of this mechanism, 30407 in this case. Ordinarily this is locked away forever when the camera is assembled, as it's hidden under the top plate of the shell.

This is the heart of the camera, the two main springs, one atop the other, sealed in their robust brass barrel. The mechanism is pre-tensioned and cannot wind down below certain point, nor be overwound, courtesy of the gear you see here on the base, which will only allow four complete rotations of the winder before locking. This keeps the spring within it's optimum torque. However, as the springs are wound up, the windings tend to bind down on each other if the grease has dried or any rust is present. This will be felt as an uneven pressure as you wind the camera, and this unevenness also makes itself apparent as the spring unwinds, sometimes to the extent that the spring has insufficient torque to do what is required of it. Despite the horrible neglect that this example has suffered, there was no rust, as the spring was still well greased, but the grease was dry and stiff. Reluctant to dismantle these two powerful springs, I elected to wash them in diesel fuel, which has excellent penetrating abilities, and also dries leaving a film of oil, rather than leaving them dry - as other solvents tend to. This did the trick admirably, and new grease was forced in through these holes. This image also betrays the manufacturing technique for the gear teeth on this spring housing. Each tooth was individually ground with a cutting wheel, the over cut being visible as a series shallow dents around the upper casing.

The shutter mechanism separated from the clockwork drive. Although filthy it cleaned up well. The wire is the flash lead, it is soldered onto the back of the flash contact, the shutter end has a spade fitting. The routing of the wire is important, as it will prevent the shutter from working if routed incorrectly. The rotary segment shutter blade, visible here through the squarish hole, is sandwiched between the black plate and it's thinner twin. The shutter does not sweep a complete rotation, the cutout sweeps the aperture at a speed governed by tension, set from the speed dial. Slow speeds are governed by a delay mechanism as would be the case in a Compur or Pronto shutter.

The shutter mechanism separated from the clockwork drive, but this time from the front. This is the secondary blind which works rather like an eyelid. When the shutter is pressed, finger pressure opens this blind before the sector shutter is released. As finger pressure is released a spring closes the blind after which the clockwork mechanism is triggered to advance the film and cock the shutter for the next exposure. During the cocking process the sector shutter has to move backwards, sweeping the opening again, were it not for for this secondary blind, the film would be exposed to light. During long (B) exposures, the sector shutter does not end the exposure, the secondary blind performs this task, so even if the main spring has wound down, the shutter will still close successfully.

The shaft protruding from the left is the shutter speed selector shaft, removing the shutter from the camera doesn't involve any complicated linkages or alignments, and the clockwork mechanism is simply attached and aligns naturally, it's been cleverly thought out to allow the shutter mechanism, clockwork mechanism and camera body to brought together from separate plants and be assembled without difficulty.

The camera would show signs of trying to work but was unable to advance the film correctly. The film canisters need to be clean to make sure they open correctly, so they were polished, but the camera still refused to work correctly. Clearly the spring was strong enough for the task, but was not feeding the film into the 'N' spool. It seemed that the drive was not able to rotate the take up spool under load, so I suspected the spring clutch.

Taking the spring clutch from within the wind on shaft revealed the problem instantly. Seen many times larger than life here, is the mangled topmost turn and anchor point of the spring clutch. It has failed spectacularly along its length, due to being forced backwards. The broken edges are not shiny or fresh, indicating the breakage is old.

It's job is to allow the user to advance the film, during loading and unloading, but preventing them from turning it backwards, which would transmit movement through the entire mechanism, potentially damaging the shutter. In this broken condition there is sufficient drag to give the impression that all is well, but not enough friction to transmit drive to the take up spool when loaded with film. After failing to make a spring that quite worked, the pragmatic solution of forming an anchor on the remaining spring clutch was adopted and the advance works acceptably.

The badly damaged film found inside the take up canister revealed these faint images. Three frames taken in rapid succession of a parachutist landing in a clearing surrounded by a crowd, his colleagues are already down with their collapsed canopies. This type of round parachute hasn't been used for displays since the early 1980s, when display teams went over to ram air square chutes. A guess would suggest the mid 1970s judging from the flared jeans being worn. The film clearly showed that the camera was becoming unreliable as several frames were overlapped, and the sprocket holes damaged. Several sections of film were fogged, where the back had been opened.

A longer sequence, where someone was testing it sat at their desk, with it haphazardly pointed at the opposite wall.

The centre frame from above and the others, reveal a tantalizing glimpse. Many old valve radios, a collection of cables hung over a hook on the door opposite, an old style telephone, UK 3 point power points mounted at various points, including one close to the ceiling. Radio call signs and idents pinned to the wall. 03UPV and ?W3NZ being discernible, though untraced. It appears to be a radio lab or maintenance office, and my gut reaction is 1970s again. Sadly the camera wasn't focussed or set to expose correctly, but as they seem to get lighter from left to right, it may have been that whoever was fiddling with it was changing the shutter speed. I see no change in focus or depth of field, so assume it wasn't the aperture that was being changed.

Anyway, these images from the final film that went through the old robot forms part of it's history, so are preserved here.

The back of the Robot after it left the workshop in June 2019. Still showing signs of it's tough life, but much improved. The badge was seriously pitted, so it was turned round polished and a new logo applied. The original now faces in. It wasn't possible to polish away all the pitting as it was too deep, but given the rest of the patina, it wouldn't look right if the badge was pristine, so this is about right.

This is how it will be displayed, still battered but proud. The camera itself works, but will serve now as a paperweight, it's considerable weight will keep any amount of paper flying around in a breezy room. The soft glass used for the Xenon's objective element is scratched to oblivion and the front and rear elements have quite a few air bubbles close to the centre. Finally, a check under the microscope revealed that the surface of the objective element is like the surface of the sea on a windy day. It's not noticeable to the naked eye. It's the sort of thing that gets described as "clear and fungus free" on ebay... In reality it's photographic days are behind it. But, maybe one of those time expired films in the fridge just may find their way into it, just to see what the effect is.

Next restoration Project page.