Bauer Studio Line Projectors with Monitor Sound Heads

[Lee McCaffrey]

Quick question, later microcomputer models like the T610 and T525 came equipped with 2 sound heads for monitoring recordings over headphones in real time (albeit with a couple of frames' delay). As sound heads are a scarcity these days it would be useful if you could swap out the second monitor head (if it was in good condition with low wear) and replace it with a 'dummy' head, or alternatively remove the head completely along with the sound pressers and replace it with a film guide, as is the case for other Bauer models.

Has anyone done this? The way I see it it seems a shame to let a sound head wear down unnecessarily, which is going to be the case for these monitor heads (unless you actually do use the monitor function).

[David Roberts]

I would not be worried about head wear on these,they seem to last well.
But the shutter cam does not.Its plastic and ive had 2 wear out recently,so otherwise great projectors fit only for the skip.

[Lee McCaffrey]

You say that they wear well but I've encountered a couple of Bauers where the heads are noticeably worn, to the point where the balance head is practically gone and the air gap is wide open. I'm sure running well lubricated prints will keep the heads in good shape for longer, although I am informed that new heads are still 'obtainable'.
With regards to the cam yes it's sad that they wear out, and the 3d printed spares are not durable. I wonder how much a production run of cams and followers made from the proper nylon would cost. Alternatively how much noisier would a metal (or more durable material) cam be?

[David Roberts]

Ive had about 6 of these Bauers in recent years,and its the cams that have gone,before any head issues,though I dont doubt your experiences with them.
If the cams could be re manufactured in nylon,at a price thats reasonable,that would be fantastic.

[Lee McCaffrey]

I thought I had a cam that needed replacing in one of my machines as there was judder but I was able to correct it by moving the claw sideways (it was catching the side of the perforation). I guess once no amount of adjustment works that's when the cam/follower need replacing.

Don't forget FFR still offer the replacement original cam and follower. Otherwise I guess it's a case of waiting for a spare/repairs machine to show up

[David Roberts]

Hi Lee,
Ive done the claw sideways adjustment too,no improvement.I even had a spanner ground down for the other claw adjustment on these.
Dont think I know who FFR are.

[Maurice Leakey]

FFR are in Germany.
FFR-Film Idstein - Your partner for film technology, narrow film accessories and cinema technology 8, 16 and 35mm

[David Roberts]

Thanks Maurice,I did track them down with Google.

[Lee McCaffrey]

As I understand it as the cam/follower wears the ratios of movement change (the cam translates to the position of the claw) and eventually the claw cycle goes out of the tolerated range of motion, at which point the claw will no longer advance film in the gate correctly no matter how much adjustment is made. I believe the follower wears down faster than the cam. I think that even with the correct silicone grease and oil lubricating the mechanism foreign debris can cause premature wear if it gets into the lubricants.

FFR's website states that normally they prefer to replace parts such as the cam/follower themselves but are open to selling parts on to repair technicians (or directly to users if the distances are vast enough), now we have quite a sticky customs border with the EU this may be something they will consider for the UK.

To get back to the OP has anyone here had experience of swapping out the monitor head (or removing it entirely)?

[Phil Murat]

Hi Lee,

About "monitoring Head", the idea is the same for Beaulieu 708 family. I have planned to test an "alternative Head" (means a little bloc including a small roller) to allow monitoring head deactivation. To be note Bauer's Heads are very , very closed to Beaulieu's ones.......and very expensive.
This small bloc is supposed to replace monitoring head and to prevent from monitoring head unwanted wear.
At this time this project is on left.

[Lee McCaffrey]

Thanks for the information Phil. I myself had thought about some sort of 'dummy' head (3D printed or otherwise) to replace the monitor head in a T610/T525. I feel this would be simpler overall than removing the head entirely and replacing the presser pins with a film guide (which is the standard layout for other Bauers without monitoring facilities). Just swapping a good monitor head with a worn one would encourage the heads to wear too far down and risk scratching the image area of the film. The presser pins seem to wear well on Bauers too without the burrs/displaced material I've seen on other makes (which can scratch, or trap lint/fibres which in turn can scratch) but some sort of roller on these would reduce wear further.

I believe the Bauer/Beaulieu soundheads are the same underlying Woelke model, with different cable configurations for each.

[Phil Murat]

Concerning this particular case I was thinking about a "Dummy" part made with aluminium and/or brass material to be compatible with magnetic tracks vicinity.
From my side , I prefer a "classical" part machining to a "3D" solution. "3D" is nice but overall precision result is limited to +/- 0,1 mm. You can do much better with a lath or a milling machine and also much faster in this case.
If you have observed a premature presses pins wear on some machine(s) , that could means their spring(s) load is over rated. For exemple , Beaulieu's Head-presse springs loads for Nylon Pins are very soft, and that works pretty well. Moreover pins do not scratch films !!
Some projectors press-pins are also too thick and need to be reshaped to prevent from encroaching frame .........
At the end, if you need a "dummy" Head only composed of static parts, all parts in contact with film could be made with PTFE material ....This is a very durable material and this will never scratch your films.

[Lee McCaffrey]

I wouldn't say any of my projectors have premature wear on the pressers, merely the expected wear for machines of their age. I always run prints lubricated so future wear should be minimal. As you say the pressers should not encroach upon the image area but if a burr forms on the presser pins then small bits of lint/fibres can catch and drag against the film, or the burr which has formed can pick up in which case it may hit the image area. I think a lot of the black lines on the very far right of a print during projection occur in this manner as the main soundstripe is directly adjacent to the frame. Obviously this may not show up until the next screening of a print, or even until a different projector with a more open gate is used.

With regards to machining of parts do you think that parts like the cam and follower can be reproduced, for projectors such as Bauers and Beaulieus which use nylon parts, or would casting be the better option?

[Phil Murat]

Hi Lee,

About Cam "machining" or "re-building , there are 2 main solutions :

1) You can copy former cam providing active profile is not worn out , putting former cam on a special device on a machine tool.
2) Using a part designer software tool (Exemple : "Solidworks") you make a suitable drawing (there is a tab dedicated to cams design), then software converts drawing to a file compatible with CNC machines.
To be note that needs to make some measurements on original part to feed software parameters.

All these projectors show 2 different cams : 1 for vertical motion , 1 for horizontal motion.

If you choose to replace Nylon material by Steel material (For Exemple : Soft Stainless steel) you will have to modify claw to incorporate Nylon followers (To prevent from a Metal/Metal contact), because lubrication is random for thes parts.
However , it is possible to mix material , Main cam (Stainless steel) and other one Nylon...

[Lee McCaffrey]

Thanks for the extra information Phil.

Looking at the two different brands (Bauer and Beaulieu) it seems that Beaulieus use a nylon cam with a metal follower integrated into the claw arm whereas Bauers use a nylon cam and nylon follower (which is a replaceable part of the claw arm). I think the nature of the nylon cam is what allows the fast pulldown action of the claw, and hence the increased light output. In contrast projectors like the Sankyos use a metal cam with a plastic follower.

From looking at photos of the Bauer's cam follower only a very small area is in contact with the horizontal/vertical cam surface, it follows that the follower would wear out before the cam itself. So hopefully David's Bauers can be resurrected with a replacement of the followers alone (but still that would require getting hold of some). Re-reading FFR's page it suggests that the gripper (claw) arm can be sent in for the replacement rather than the whole projector which would in theory save on costs/shipping but would require removal/refitting of the claw plus all the alignments to be performed by the user at home.

Considering the small size of the follower compared to the cam it may be possible to have these made in bulk, alternatively a re-usable one could be made (either machined or 3D printed) into which small nylon inserts could be fitted and replaced as necessary. Nylon rod is easily obtainable in most diameters and would simply need to be cut to length.