What's New 13
Doesn't seem to take long to fill up a page; in the interests of keeping them relatively short, I've started a new page 13. First, a brief message from our Sponsor. (You do realise this is a joke, right?)
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26th January 2021
Although it's a bit esoteric, this is after all just a blog about what I have been doing so...........
This is the sound unit for a 16mm Rural Sonore. I am looking at the possibilities of conversion to 17.5 by running the film thru the "wrong" (for 17.5) way, not so much because of the sound unit but because of the problems with the claw and cam. My previous attempts to dismantle one of this design failed because of the difficulty of getting the sound drum out, which is held in 2 ball bearings and did not want to shift. In the end, I 'it it wiv a 'ammer (cushioned by a piece of wood). Note the clever design which provides a big space for the motor capacitor and the sound drum, exciter (from the projector main lamp) and photocell, all in a single layer which could mount directly between the silent Rural's base and mech sections. This 16mm version obviously followed on from an original design for 17.5.
As usual, the paint was coming away in large areas, with some aluminium rust (you know, that white stuff that so often appears on elderly alu etc castings), so I decided to strip it back. This reveals how rouigh and ready the casting is in places. The fettling (this is, I believe. the correct technical term for machining the rough bits from raw castings) is precise only where it needs to be, eg in the tube that contains the bearings - pic one far left. Elsewhere, it was a lower standard - see pics 2-3. In fact, pix 3 and 4 make me wonder if the square section and the twiddly bits were made separately (which would be a lot easier to cast) and welded together after. The problem is that one cannot realistically re-paint over the old - it just looks scruffy, but duplicating the very thick paint finish that hides the multitude of underlying sins is a problem. Hand painting never looks right, but spray is pretty thin and shows all the dodgy bits. There is also the question of adhesion - one of the reasons so many old machines tend to lose their paint finish is that alu etc needs a special etch primer for the paint to stick, and the correct procedure was not always followed. I have a Vox that is almost bald because I was able to flake the paint off with little effort.
Pic 5 shows the bits that survived to now. The sound drum - necessarily very small because of the design - is basically a single unit comprising the shaft with drum, 2 ball bearings and a spacer to go between them. The ball bearings had seized up, but improved with soaking in white spirit and oiling. I spose they would work, but I would ideally like to replace them. I have however discovered that bearings with a 10mm centre, 26mm outside diameter and 8mm thick are ten a penny. Unfortunately, these ones are 25mm diameter , 10mm centre ,8mm thick and a preliminary search has completely failed to find any. Usually in the past I have easily been able to source replacements for various French machines as they have been standard metric sizes.
The tube for the photcell is obvious in the pix, but the little cone thing, which has a curved mirror placed across its axis, puzzles me as I have seen only direct reading versions before. It must have worked tho'. The pressure roller for the sound drum is really crude - mounted on an arm that is just a piece of steel twisted to the required shape.
13th January 2021
Here's a bit of detailed restoration sort of stuff - it's about the 17.5 Rural.
The original silent Rural was introduced in 1927, too long after 16mm to have much chance in markets outside France. In 1933, a piece of clever engineering added an extra layer to the existing two tiers to create the Rural Sonore. Then in 1941 the Germans demanded that all 17.5 machines be converted to 16mm. Some did survive as 17.5, but most were converted. The original Rural silent had only 500' capacity - a single reel. The sound machines had longer arms, to suit the 1000' (2 Reel) spools that became the norm for features and the like. This was not good enough for 16mm of course, so yet more adaptation increased capacity to 1600', which I think will be just enough to take a 2000' spool, to make life a bit easier for projectionists showing 8 and 10 reel features.
I am gradually getting to the point. I wanted the bigger (1000') spools for my 2 silent Rurals, so when I acquired some 16mm versions of the Rural Sonore it was party with an eye to stealing their spool arms as well as various other common parts. Given that some of the 16mm machines came without arms, the net result has been a shortage of said arms, so I am having to re-condition those I have got as best I can - and not all of them are complete. The one I have just been dealing with has the take-up assembly missing from the lower arm. I have therefore stolen one from the now-unused 500' arms and in the process discovered a style of friction brake I had not previously seen. Yer tiz.
The friction is provided by the four little "brushes" bottom left. The springs fit in the transverse holes thru the adjacent disc, which holes are partly exposed as seen. The brushes fit one either end of the springs, and the disc, spring and brush unit fits into the hole provided in the pulley wheel bottom right. The rest is obvious.
Experience in recent weeks testing a Rural Sonore makes me feel that this friction mech is necessary for correct functioning of the machine. The drive to the take-up is a standard wire spring belt but it needs to be thick and fairly stiff to work. This in turn means that the springing is too stiff to rely on the flexibility of the spring to avoid excess stress as the film comes over the bottom sprocket, as many smaller projectors do.
I very much doubt that the assembly has ever been taken apart since 1927 as it was so filthy and it took a bit of work to remove the accumulated gunge of the years.
I have also added an update re the sound unit near the end of the second page under Rural Sonore.
12th November 2020
I have spent much of the last two days doing exactly what I was suggesting, ie building a mounting plate for a standard Vox sound telescope unit. Both it and the LED exciter work well. As indeed does my fingers-crossed repair of the sound smoothing unit. Must copy both asap. Will do you some pix.
10th November 2020
I have been making a further assault on making a sound head for the Rural Sonore. Details are on the third page under Rural Sonore; here is a link.
22nd September 2020
I have been renewing the pictures on the 22mm page - the Edison Home Projecting Kinetoscope. In the process, I came across a pdf I had acquired years ago and forgotten I had. It contained an article by one Ben Singer, titled Early Home Cinema and the Edison Home Projecting Kinetoscope. I don't want to breach copyright by including it here, but the full reference is Film History [an American mag of course] Volume 2, pp 37 - 69: 1988. It should be easily available for private study. The article contains fascinating stuff about the early years of Home Cinema, including one or two remarkably accurate contemporary forecasts of where it would end up - not far from what we see today. Just as interesting is the extensive list of references and sources, giving an idea of what a range of information lurks out there - not just 22mm but the home cinema hobby in general -awaiting someone with the time to research it and, more important, communicate it to the dwindling band of home cinema afficionados. And this was 1988 - there must be a lot more stuff now.
I have also been engaged in one of my prolonged fights with a recalcitrant machine, a Specto in this case - it all takes longer than it used to because of declining mental and physical capacity. This is an 8mm machine that came to me while in the process of being converted to 9.5mm, and was not working. I have learned a number of new things and quirks of the Specto. Among these are the method of attaching the (fixed) front gate to the lens carrier. Just doing this job identified 2 and 4 screw versions; there may be more. I also learned the importance of a very small washer/spacer where the claw retracting lever interfaces with the rear claw spindle. In trying to position the claw, I found that I could only do this by removing the entire gearbox assembly so that I could watch what was happening. In this way I discovered that the claw was fouling the lens carrier, where the cut-out needed to stop this was not wide enough, due to differing requirements between 8mm and 9.5mm gates. There is also the issue of different shaft sizes for spool spindles and the chain sprocket drive. In short, I have come to see that if I wanted to get to my destination, I really should not have started where I did.
14th September 2020
I have completely re-done the page Film Dimensions, formerly film standards and sizes, in my campaign to update the site.
21st August 2020
I did manage to finish the Super Vox and make it run and produce sound - a rare victory for my side in the constant battle with projectors. I couldn't get anywhere with the Vox so have set it aside for another day.
In response to a request from a user, I turned my attention to the Ampro page and re-established the pictures. The last part was about the Premier model. This machine is one of the basic reasons why you are reading this today. I saw one in the Buckingham Movie Museum and was utterly entranced by it and it was part of what made me build a much bigger collection and ultimately start this website as a sort of personal replacement for the Museum. I was so enraged and disappointed by the lack of anything else like the Museum, tho' I did introduce a section for home movie machines when I was with the PPT, when it was at Bletchley Park. I suppose this is a virtual Museum in some ways.
15th August 2020
I have spent quite a bit of time just existing during the recent spell of extremely hot weather, up with which I am not very good at putting. In between times, I have done quite a bit of website work on pre-war and post-war Pathé Equipment/General catalogues, which seem to have been quite poor in their original form so have required a fair bit of work before re-inserting (Catlogs). Still one more late one to insert - any more out there please?
I have been having the expected trouble getting the Super Vox back together again, with problems over the mech being very stiff and impossible for the motor to turn. I think I have now overcome this but, as ever when you have to do major dismantling, collateral problems occurred and I am now having problems with the amp. Rather than get on and finish the Super Vox, I turned to a Vox that I had obviously worked on in the past (I don't remember doing it tho'). I found the wiring was not right, presumably why I abandoned it before, so have been semi-concurrently meddling with that.
2nd August 2020
Been plugging away at my inventory, which frequently gets interrupted by examining projectors to establish their status and all too often trying to figure out how to make them work. Most recently I looked at two Kodascope Model K machines, one a plain K and the other a K-75 The plain K responded OK without much work but it and particularly the K-75 needed the application of a bit of brute force. This was supplied in the case of the K by removing the inching knob and latching a cordless drill to remind the mech how to turn. The K-75 got a more manual approach as my cordless wasn't big enough for the inching knob wot I couldn't be bothered to remove (it uses one of those transverse pins to secure it to the shaft and they can be a nightmare to knock out), so I used a drill chuck from my lathe, mounted on a taper thingy, which was big enough. Neither of these machines has done anything to remove my dislike of Kodascopes in general, being very much like the L which gave me so much trouble a year or two back. One of them had rotted insulation on one of the wires to the motor speed control. This extended right back to the motor casing and it was simply not worth trying to take the motor out and seeing what could be done. I settled for re-insulating the offending wire with heat-shrink and then dripping liquid rubber insulation (after these pix were taken) onto the point where it passes thru the motor casing.
I have also been contending with a Super Vox with a type of fault I had not encountered before, at least, not in the location it turned out to be in. Basically, the drive train from the motor to the various parts of the mech was breaking down intermittently and "missing", rather like cars in the bad old good old days and in particular leaving the bottom sprocket running normally while the rest hesitated from time to time. The results were not good. It rapidly became apparent that the fault lay inside the mech casing. This means taking the side off, which means taking the motor off which means unthreading the motor wires from its connections in the base. In this case, the machine had been well "got at", with a modern solid state amp in the base and a big tranny in the old amp case for a 24v tungsten halogen lamp. Seems a little perverse, but the tranny apparently to hand at the time was too big to go in the base. Why not then, you ask, simply remove a few turns from the secondary winding of the original tranny to get down to 24v? One of lif'e's little mysteries. The whole thing has probably left the machine heavier if anything.
Anway, to cut a long story short, I traced the problem to the interface between a fibre gear and a brass gear, one of them having its threads heavily worn away. Contrary to all my expectations, it was the brass gear that had worn and the fibre gear, though somewhat affected, appeared still functional. For a long time I believed fibre gears were for quieter running; later I was told they were there to be a weak link in the chain, one that would fail before anything else did. Perhaps that applies only to catastrophic failure rather than wear over time. Let me start with this pic.
This is a view from the rear of the machine,ie opposite to the direction of projection, and from the back, ie the side opposite the sprockets, switches etc, and with the machine lying on its front side. From the left, we have a lage brass gear; this is mounted directly on the main shaft, which carries the motor speed change gears at one end and the lower sprocket at the other. Next we have a small fibre gear (this is the replacement I have fitted), partly hidden by another brass gear. What you cannot see is that the fibre gear engages with the lower end iof the brass gear, which is about 0.5" indiameter, as well as the first (large) gear, so we have two stages that increase the speed of the drive. There was sufficient play in the system to allow the fibre gear to lose contact with the large brass gear on the left, so intermittently failing to drive all the rest of the mech apart from the bottom sprocket. Also unseen is the fact that the fibre gearshaft, on this machine at least, passes through into the claw chamber where the end of the shaft serves as an anchor for the spring attached to the bottom of the claw itself. The shaft of the right-hand brass gear carries at its other end a circular disc to which the claw cam is attached. The bearings for these shafts are faily thin, in the main mechanism casting.
Just to complete the drive train, here is an overview. The gear on the outer rim of the second brass wheel engages with another fibre gear - another significant step-up in speed - on which is mounted the shutter (out of pic to the right). Then we have a small speed reduction onwards to a major speed reduction via the final worm drive to the gear on the top sprocket. These final two stages are shown in close-up in pic 2 above.No doubt you are well ahead of me here in noting a major speed rise up to the shutter, all of it then shed to bring the top sprocket speed in line with the lower. In the Vox, this is avoided by the use of a direct chain drive from top to bottom. Much more on all this above. I don't know why they changed from chain to gears, but it explains one thing; the metal plate forming the side of the mech is identical in Vox and Super Vox, apart from a small displacement of the bearing for the top sprocket shaft, necessitated by the size of the gear needed to bring the speed down for the top sprocket.
Now we get to the meat of the matter. I had to remove the hefty brass gear (some flywheel/stabilising purpose?). This was secured in place by one of those abominable transverse pins, which go thru a hole, tapered all the way, thru first one side of the gear, then the shaft, then the other side of the gear. The original gear also has a grub screw for good measure. Over time, these pins seem to seize in place and can be the devil to remove; this was not the first time I have had to resort to drilling to help the pin out. I found a box with all the gear train components of another Super Vox to enable me to replace the hefty brass gear and the fibre gear. Here's why.
The two gears in pic 1 are the originals. you can just about see some scoring round the rim of the fibre gear but the real damage was to the brass gear, best seen in pic 2. It is hard to say whether the chicken of looseness in the way these two gears were mounted came before the egg of damage to the gears or vice versa or, indeed, a bit of both. But it meant I definitely had to replace the brass gear and felt it sensible to replace the fibre one, too. Here more anomalies came to light. The pin in pic 1 was from the replacement fibre gear, and has a diameter to match the hole thru the gear. However, it is much too short to do the same job as the one on this machine. Instead, the fibre gear fits over a spigot on the body, then this is held in place by a thru rod - in this case with a screw thread along its entire length. It is then secured inside the claw chamber with a couple of nuts, leaving a short length for the claw spring to attach. The screwed rod was smaller in diameter than the hole thru which it passed. Now, this should not in principle affect the centricity of the gear, as it rotates around the spigot on the body, not the rod, but it still didn't seem right to me, so I replaced it with an M3 machine screw. It was then a matter of careful selection of washers to ensure the gear is held tightly in place but still free to rotate.
The rod in pic 3 above serves as the shaft for the brass gear; this one however lacks the circular disc which is force- or heat-fixed onto the end. The claw cam then fits onto this disc. If the disc comes off, as here, I'm not sure if it can reliably be re-attached. Not a problem here anyway. The replacement brass gear still seems to have provision for one of those transverse pins, but it also has two grub screws, plus a flat filed onto the rod to give one of the screws a much firmer fit. I am hoping this will work without a pin.
That's about it, except for the part I don't like, which is putting the whole thing back together to see if it actually works. I shall have to completely re-assemble the machine as there is no half-way stage at which I could stop and test before moving on - it's all or nothing.