This is topic Rank Aldis automatic in forum 16mm Forum at 8mm Forum.
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Posted by Maurice Leakey (Member # 916) on May 04, 2008, 03:20 AM:
We have been talking recently about Super 8 Chinon projectors and the fact that they have part plastic gates, which could, at times of wear, cause film scratching.
I was using one of my 16mm Rank Aldis automatics (made by Bauer, I believe) last night and after the show took off the front gate assembly (easy to do with the removal of one long pin) to clean out the gate.
It was surprising to find that the front pressure plate is plastic. I've had this projector for years and never even thought about the gate until the recent Chinon correspondence.
If you have a similar projector, have you had any problems with film scratching? I can't say I have.
Posted by John Whittle (Member # 22) on May 04, 2008, 02:20 PM:
The later RCA 400 series had a nylon front pressure plate. The biggest problem I would think would be heat distorting the plastic but as the technology has advanced it's probably a cheaper and better choice than metal and plating.
John
Posted by Michael O'Regan (Member # 938) on May 04, 2008, 05:06 PM:
I had exactly that problem with a Bauer P8.
Over time heat caused distortion of the pressure plate causing uneven pressure against film and gate resulting in jitter.
-Mike
Posted by Maurice Leakey (Member # 916) on May 05, 2008, 04:24 AM:
When I used the word "plastic", this is a generic term which would include "nylon."
I looked at the photo of the Bauer P8 in Jurgen Lossau's book "Movie Projectors" and it looks similar to my Rank Aldis, althouh the P7 looks identical. I have two projectors, one takes an A1/223 lamp, and the other which is an obviously later projector uses an A1/259 lamp, it also has a still position selected by a red sliding knob near the mains entry socket.
It's quite small to look at, but, what a weight!
Posted by Josef Grassmann (Member # 378) on May 22, 2008, 11:16 AM:
Rank Aldis projectors had been built by Bauer (P6, P7, P8).
All three basic types use a plastic pressure plate (different shape in P6,P7,P8). That plastic part is very reliable and last for a long time. Even earlier Bauer P5 series (fifty years ago) had a plastic pressure plate employed.
The opposite metal film guide might cause scratches, if deposites had been removed with a srewdriver or knife.
Unstable picture / jitter is often the result of worn or disjusted claw mechanism due to lack of grease/oil on cam or wrong grease used. Original Bauer Grease is of white colour and very soft, with a high oil content.
Posted by Josef Grassmann (Member # 378) on June 25, 2008, 04:08 PM:
There is one way to destroy plastic pressure plate by heat.
If projector is running with light on, without film and lens holder is opened "half way" the light beam canīt go through apature and hits onto black pressure plate. After short time pressure plate will deform. Often seen on P6-series.
In order to avoid it, Bauer employed a spring and a black plactic piece at hinge of lens holder on P7 and P8. That spring opens lens holder full way, so that light beam canīt hit onto plastic pressure plate.
There have been update kits available for P6 and earlier P7 (spring and black plastic piece)
Deformation of pressure plate does not take place during projection with film.
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