Film-Tech Forum ARCHIVE: Portable 16mm Projector

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Topic: Portable 16mm Projector

Lindsay Morris
Expert Film Handler

Posts: 233
From: Darlington, WA, Australia
Registered: Sep 2002

posted 04-23-2004 10:30 PM

The Bell & Howell film claw mechanism is probably the best ever designed as far as claw type movements go... nothing can compete with the Maltese cross style on 35mm machines or some upmarket 16mm machines.
Eiki, Elmo, Hokushin, Bauer and others all use a very similar drive method for the claw which is simply a single pivot at one end, the claw on the other and driven up and down and in and out by a cam. The result is that the claw does not move exactly parallel to the edge of the film... it works over a very small area of an arc determined by the length of the arm it is mounted on. This means at the beginning and the end of each claw stroke the teeth of the actual claw are at a point close to the edge of the sprocket hole closest to the image and in the middle of the stroke are towards the edge of the film.
For this reason any shrunken or poorly spliced film does have a few problems as the claw teeth are actually sliding left and right within the sprocket hole area as each frame is pulled down.
Bell & Howell on the other hand have a twin arm system so pivotted and driven that the claw teeth move parallel to the film edge throughout the stroke... or so close to it that it does not matter.
In addition B&H claws have 3 teeth whilst most others only have 2 teeth so again very reliable film movement is possible as more than 3 consecutive sprocket holes have to be ruptured before the B&H units start to "stutter" and kick in the loop restorer.
Although many professional projectionists.. such as on this forum deride "auto loaders" they did have a place when many schools and similar had 16mm machines and getting all the various "users" of those machines competent at lacing a 16mm machine and not wrecking film was a HUGE task and never really achieved.
So the autoloaders arrived and most were quite OK and IF kept clean and regularly serviced and IF the operator fed the film in the correct way there were no real problems.
16mm has only one set of sprocket holes and the sound is on the other edge and I have prints here where an "operator" repeatedly fed a 16mm feature into a front loader with the sound track on the outside edge and in the finish actually got some form of perforations going such that the film was being fed thru for quite some time before they stopped the show as they had no sound and the image was back to front.... [Eek!]

That film now has a nice plop plop plop sound for the first 30 or so metres due to the scratches/indents on the sound track.
Amongst the B&H autoloaders the slot loader Model 1680 is probably the best one to hunt for as getting film out of any of the other B&H's (the front loading type)was always going to damage film unless you worked VERY carefully.
Cracking worm gears are a problem for all of the later model B&H machines from series TQ1 onwards and was particularly a problem in Australia due to the wide temp ranges we experience but here there are at least 2 known aftermarket makers of excellent worm gears that once fitted will probably outlast the machine.
The Eiki slot loader SL1 & SSL1 are both quite good performers with good light and good sound and some have a Aux O/P socket inside the back cover for feeding into a higher powered sound system.
The Hokushin circa-loader SC10 is another good performer with equally good light and sound in comparison to both Eiki & B&H models. The "circa-loader" is a strange looking beast where the end of the film is clipped into an external arm at the top of the machine. Press the Thread button and the arm swings around through the sprockets (2) and the gate and sound head and stops ready to poke the film into the takeup reel. An internal cam system attached to the arm opens the gate as the arm passes around "laying" the film in the slots and then closing bits as needed afterwards.
Quite nifty to watch and once threaded up has a safety switch unit that prevents that arm being activated when the machine is rolling. Has nice BIG diam sprockets that are very kind to film and is very easy to unthread should you have to.
The Elmo 16 series which was quite common in Australia is also quite a good machine with good light and sound BUT has a nasty problem of leaving horrible sticky goey deposits on film and almost wrecking a print as there are 3 or 4 rubbers rollers thru the sound drum area that tend to break down with both heat and over-lubrication and instead of being firm and clean become mis-shapen and sticky and leave great trails of black dobs of disintegrating rubber on any print unlucky to be run thru.
So check any Elmo machine carefully for rotten rubber rollers.
B&H 1680 also has a similar rubber roller/pinch wheel for the sound drum but I have yet to see one break down quite like these Elmo units did.
The Bauer/Rank units were also quite good but some with the auto load had a tendency to jam the film as it passed into the gate with often damaging results for film leaders.
Most of these machines that used Halogen lamps of the 24v 200/250watt versions had quite good light up to images of 4m wide in average conditions or you could push them to 5m wide in a good dark room with a good screen.
The older machines with 750 -1000watt lamps were no real match for a later unit as the light almost always was yellowish and nowhere near as bright and crisp as the Halogen powered machines.
In addition the later machines had the benefit of faster lens in the order of f1.1 on some to f1.3 on others..older machines could often only muster a f2.0 lens which consumed a fair bit of the light.
My personal choice would be a B&H 1680, Hokushin SC10 (with the Hi Lo lamp switch), Eiki SL1 or SSl1 and Elmo 16CL and then Bauer P6, P7 etc.
The only criticism of the B&H units is that they went to DC drive rather than a synchronous mains motor as all the others use and in doing so created problems with tiny fan motors that frequently run out of brushes when you least expect it and motor speed control electronics that was under engineered and often quite erratic.
I have 3 B&H 666 machines which have a sync mains motor are manual threaders and use Marc 300 lamps. Rock steady image, very bright up to 7 or 8m wide, good sound but very heavy and lamps are expensive and sometimes hard to get. As well they built in a push botton change-over system and IF you have the coupling cable is brilliant for 2 machine operation.. works like a dream.
Lindsay [Smile]