KOK

 

 

PATHESCOPE KOK 28MM PROJECTOR

 

KOKs5     KOK2413b      KOK3539     kokad     KOKebay     KOKfs

 

 KOK     KOK2714a     mains kok_2a     KOK Seydoux     paris 2009_008b

 

Here are various random images of KOKs as a starter for 10. The trouble with KOKs is that after a while they all start to look the same; it's ther exceptions that are interesting and there are of course all sorts of things that show past interference/repair, even maybe improvement, eg a front shutter and better lens. The last 2 pix are very special - one is filched from the website of the Fondation Jérome Seydoux - I did mean to use a link but it was so long I decided against - and is in superb condition - it looks like the transfers on the side of the mech might even be legible! And then the grey one. The motor is very obviously designed in and a large inching knob has replaced the crank handle. This one was in the equipment stacks of the Cinémathèque Française.

My first KOK had been modified and was also suffering from the paint flaking that afflicts so many Pathé machines,  usually because of exposure to damp. All in all it looked scruffy. I stripped it down quite substantially, and carefully re-sprayed parts of the machine, tho there was little I could do about the fading transfers. I gave particular attention to the generator/dynamo, which made a sort of grinding noise on rotation. I stripped it right down to look at the bearings, which I suspected as the source of the noise. To my considerable surprise, exact replacement bearings were readily available. It was a major job to get the old ones off in the end I had to grind them off, totally destroying them in the process and taking great pains not to damage the windings and commutator. Getting the new ones on was hard I had to hit with a mallet far harder than I really wanted. See "before" pic below. 

Then it was re-spraying and re-assembly. On test (feeding DC in to use it as a motor), I was relieved to find it still ran. I could get no joy out of it for light, however. Even a 6v 10w QI lamp showed not a glimmer. I suspect the permanent magnets have weakened. I did consider having them re-magnetised, but was discouraged by the huge cost I was quoted. I used one of those modern lighting transformers in the end. Pic 2 below is after.

 

KOK2029pre     kok2029post     

I decide I could not justify (or afford to keep!) two KOKs, so I sold that one. My other, a non-dynamo machine with a large lamphouse and a much smaller crank handle (row 2 pic 3 at the top of the page), was in much better condition. Apart from the cover. This had rusted badly and the splendid transfers on the outside were almost invisible, so I reluctantly sanded down and re-sprayed. Although I had the fittings on the cover, and one of the bolts that secure it to the base, I did not have the second bolt or the fitments for the base. These are sheet metal folded in a complicated way, and I spent hours making rough replacements. All the originals were rusted, and quite pitted, so there is a limit to what can be achieved by way of quality of finish. There is, however, a vindication of that most important dictum:

NEVER THROW ANYTHING AWAY!

I cannot emphasise this too strongly. If you must take bits off projectors or do even worse things, at least keep the old parts. I found in the bottom of one of my "bits" boxes, a KOK sliding bolt, that I must have had since about 1970. The knob was broken off (and the one on the other bolt came off in my hand), but that was not too hard to re-manufacture.

Having sold one KOK, I managed to end up with another, purchased in France.

ArgKOK1     ArgKOK2

If you look above and left of the sprocket, you can see a shiny lever, like an elongated teardrop. If you operate this while cranking, the mech stops to give a still pic. It's clearly an original feature, but nothing I have ever heard of before. The knob on the front is to move the shutter out of the way if necessary. This may be the origin of the front-shutter KOK in the opening pix (top row No. 6), which I can't now recall where I found.

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KOKs1     KOKs2     KOKs3     KOKs4

Two KOKs of the decrepit variety, which I purchased along with a third which has little more than the frame left, as a restoration project. I need another restoration project like I need a hole in the head. There is a dynamo, which I had already removed before taking these pix. On closer examination, I have found I can probably get two working machines - one a dynamo model, one a mains version - barring a couple of tricky bits - no lamphouses, only one lens and only one (decent) arm/top roller. So I have spent a huge amount of time in my workshop, making a start. First bit was to dismantle, repaint and give new bearings to the dynamo. One of the things I would have liked to do was to get the dynamo re-magnetised, but this is far from as simple as it looks, from what I have read. I have yet to find anyone who can do the job, let alone at a reasonable price; it would, however, be the only way to make a proper assessment of what the light output might have been from a KOK when new. Not that it would mean a lot - I am just reading Bill Bryson's latest, At Home. One of the points he makes is just what incredibly dim levels of illumination people made do with before electricity became widely used; he uses as illustration a picture of four people around a single candle on a table, all doing things like reading or sewing, in light we would regard as little better than darkness. I also found out something rather disturbing; it appears that disturbing magnets in any way, let alone dismantling as I did, has a very deleterious effect on the strength of their magnetic field. Be warned.

 Kdyn1     kdyn2

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Jan 2012

I've now stripped all the components from the KOK I'm working on (the one the Dynamo above is from), and have also removed all the loose and flaking paint. The pix are repetitive, but for a reason.

 kok frame_005a     kok frame_005b     KOK frame_005     kframe1     kframe2

kok frame_002b     KOK frame_002a     kok frame_001a     kok frame_003a 

The repeats of the same pic are just to test, first, different camera settings and, second, different backgrounds and ways of tweaking the pix. The last pic is an unprocessed example, just to give you an idea. I'm trying to decide which shade of blue shows up the detail best and to eliminate oddities such as the way the colour of the background is reflected in parts of the image, which I find unhelpful. You can see the pink tinge in the centre rear of the first pic on row 2. What I tried in the end was to cut the blue, then convert the image to greyscale and back and then re-paste the blue. You can see the result in the first two pix. I appreciate this will not be of much interest to most of you, but it's all part of trying to optimise the quality of the pix in Cinerdistan.

Anyway, to return to our muttons. Can I first draw your attention to the first 3 generally identical pix. You can see the vertical upright part of the frame at the front displays evidence of where two parts of a mould must have met, with some excess material emerging (although it has mostly been fettled clean). This line extends all the way round the perimeter of the frame and round some at least of the internal "cut-outs" in the frame. The significance of this is much the same as the fact that, where the paint has flaked off, there is a slight "step" in the surface. The problem is that, in my experience, any unevenness in the surface becomes glaringly obvious when spray paint is applied. I do not have the capability to re-create the thick paint layers that seem to have prevailed on old projectors, so I have to get the surface as smooth as possible to avoid defects showing up. Maybe I am being a bit perfectionist, but it does seem to me that a restoration is expected to have a higher standard of finish than even the mintest of originals. This means a lot of work sanding, using a mask and goggles as there is probably lead in the paint.

When and as I have had the chance, I have been beavering away in the workshop on more aspects of KOK restoration. Here are some pix.

 koktrsfr

One of the biggest problems with any KOK restoration is those damned transfers/sign writing/lining etc on the mech, the base and the cover. Usually, they are faded and damaged and, if not, how do you paint round them? You could spend a fortune on a professional job, but how many of us can afford to do this? So every now and the I tinker with photo editing software, where the only cost is my time. This is is a bit of a clean-up of the cockerel on the front of the mech. 

 

KOKlens2     kok lens_001a     KOK lens_002

These three are a new lens mount. I always seem to have the problem with Pathé machines that it is next to impossible to to find an alternative lens that will work (I had this with the 17.5 Rural). While fiddling about trying to find something - anything - that would actually give a focussed pic, I found an old-style B&H 75mm lens unscrewing in my hand into a front and a rear section. The lens in the rear section seemed to work, so I set about making both a carrier for this lens (which I had to hack bits off) and a mount to sit on the front of the projector. I have yet to test this out thoroughly, but it appears to be quite a short-throw lens.

It being Xmas and all and impossible to get hold of anything new, I worked with what I had, principally a length of thick-walled aluminium tube of about the right size. It was fine for the lens carrier, but really just a bit too small in diameter for the mounting.This created problems in that the screws thru the front plate of the mech that fit into the perimeter of the mounting have very little material to go into. The spring-loading on the ball bearing that tracks in the spiral on the outside of the lens carrier, to allow focussing, also doesn't really have enough depth of material to work with. I suppose I shall have to do a detailed drawing, or I shall have no idea what to do if ever I need to make another - all this working out what to do and making a prototype is very slow and time-consuming.

I have now done a pretty pic of the KOK lens fitting.

KOK lens_carrier_drwgB

The reasons why all the dimensions are a bit odd are a) prototyping with materials to hand and b) presumably most of those who do metal-working at home are elderly nerds trained in Imperial measures. For this reason, it is very hard to get hold of materials in small quantities in Metric sizes. I, on the other hand, came late to all of this and found Metric much easier to work with, even tho' my lathe is Imperial. So the alu tube used for this job is Imperial, with a 1" bore. As I have previously mentioned, in an ideal world, I would use some slightly bigger tube, both for this and for part of the lamphouse, q.v., which would give a more satisfactory solution, tho' sizes would still be odd. 

Some more pix of the lamphouse and lens I've made for the KOK - as much as anything, these are for my reference when I've forgotten exactly what I did - probably the end of next week.

KOK lens_005      KOK lens_004     28 lamphse_10     28 lamphse_11     KOKLH     28 lamphse_08     koklh2     28 lamphse_06

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From among my KOK bits, I have ended up with a spare mechanism, which has obviously been painted over at some time in its history. I had no qualms, therefore, about taking it apart to see what makes it tick. The mech is actually pretty simple, as there is only one cam, in and out movement coming from the sprung claw instead. Here are some innards pix for you.

kok innards_008a     kok innards_004a     kok innards_005b     KOK innards_009

The most complicated part is the shuttle, ie the up and down slide operated by the cam. The final pic above shows you some close-ups of how the claw works - the intrusion in 3 is a screwdriver to push the claw into (in fact well past) the point it would get to as it is forced back by the film as it (the claw) travels back up for the next stroke. The shuttle has to have the extra fitment to which the claw spring is fixed and which serves also as the stop for the claw as the spring pulls it into engagement with the film. It then extends further to provide pivot points for the claw frame.

What I was particularly looking at, however, was the shutter. It's a simple, one obscuration per frame jobbie, which will of course lead to flicker if the pic is at all bright. I think if I undid the screws you can see in the second pic above, and removed that pin, the shutter would simply slide off. I could then fabricate a new one. I was wondering about adding two additional blades, each of the exact width of the picture aperture. I theorised that all that was needed was an obscuration, but it didn't need to be as long as the obscuration of the main blade, which has to cover the movement of the film as well. Hopefully, a higher-power lamp would more than compensate for the additional loss of light to the shutter. Can anyone comment knowledgeably on this? At least, I now have a way of experimenting, since the mech is only secured to the projector body by 4 bolts and I can easily swap it to a working machine. I also want to look at the lens question - the hole left after removing the lens mount is 30mm; hopefully it will be possible to find a decent replacement. Note that, as usual, the aim is to avoid any irreversible changes.

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Some lucky people have KOK covers in good condition; here are some from Willem Hackman.

KOKcover8     copy 2_of_kokcover1a     copy 2_of_kokcover4a2     kokcover10a

Even more beautiful is this restored KOK and cover, the picture of which came from Brian Giles, tho' I don't think it's his.

BG KOKa

 

Couple more random KOK photos; might as well be here as sat on my computer. Brian Giles again.

b giles_kok_2b2     b giles_kok_3a2

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I did some work on a KOK for a friend. Some fiend had removed the original lamphouse and replaced it with an amazing abortion of bent tin and thick plywood, with gaps you could get your finger thru. Very horrid. I made up a new lamphouse, using dimensions from my mains KOK. I then discovered that the arm that supports the top guide roller was upright, suitable for small lamphouses such as had obviously been fitted to this KOK. On my large lamphouse machine, this arm is swept right back. I therefore had to make a new arm to allow me to fit the new lamphouse.

kbkok3a

The dynamo worked; at least it went round as a motor when given a DC supply. The original lamp was, according to someone who has some, 6.5v 0.7amp. Odd, and not enough to provide useful light by todays standards. I did consider using the dynamo as a motor to drive the machine, but the magnets will have weakened over time and I doubt it would be man enough for the job unless over-volted, with the risk of burnout. (On subsequent consideration, one might get away with it if it could be started by handle and the handle could be removed when the machine is up to speed. The KOK handle does not lend itself to this, tho oddly, the Premier one does.)

kbkok1a

I have made the new lamphouse without making any change to the original projector. It fits over the ring that is held to the back of the gate by two screws (part of the original lamphouse which somehow survived butchery.) The new one is, as per the original, a push fit over this ring. It needs a firm push, but I deliberately left it stiff. If you need to change the lamp, you undo the two screws retaining the ring, take the whole thing off and then put a finger in and pull the ring free. Only do this when the lamp is bust as you can't avoid touching it and they don't like it.

 kbkok2a

The original lamphouses have sort of light-trapped vent holes for cooling, standing proud of the main diameter. This is beyond my skills and probably not enough for the new lamp, so I fitted a small fan, which takes its power from the lamp feed. It seemed to manage a full 400ft reel without getting too hot. It will, however, burn the film if it is stationary in the gate. The new lamp is 12v 50w QI; it might be possible to use the 100w, but I erred on the side of caution. While I was at it, I put some woodworm killer into all the flight holes I could find in the base. I also put glue on the worst of the peeling layer on the underside. I would emphasise that nothing I have done has involved any irreversible change to any original feature of the machine as received. Nor did I discard the dynamo brushes or the original, smaller arm for the top loop guide.

The power supply comes from a rather tired old Eumig P8, which had a 12v 100w lamp. I considered just removing the tranny, as I have done before, but this means a new box to be made, so I have simply left it in the projector, which already provides an adequate box. Why take out the tranny and make a box for it when it is already in a perfectly good case? I took the brushes out of the motor so it wouldn't run. The 12v output for the lamp is switched on and off by the motor switch of the projector. All you have to do is plug in to the back of the P8 and connect the spade terminals to the KOK dynamo connections, leaving the existing spade connectors in place. I've removed the dynamo brushes too, so no power should go to the dynamo. The power then uses the original wires to the lamphouse. In the alternative, you could buy one of those lighting transformers. The other thing I did was to redirect some of the lamp feed to a small (40mm) 12v DC computer fan fitted to the back of the lamphouse to provide just a little cooling. A small bridge rectifier and capacitor was used to convert to DC. A 12v 50w QI lamp managed a full 400ft reel without the lamphouse overheating.

 

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KOKebay2     KOKebay3     KOKebay4

Here are some pix from eBay. Note the resistance and the rewind attachment!