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Adjusting Acme optical printer shuttle movement pressure


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I need to adjust the cam on my ACME optical projector to adjust the pressure in the shuttle movement so the film is held tighter in the gate.

If anyone around here knows a technician familiar with optical printers please let me know.

thanks!

 

 

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The bearings are fine, I have many movements (vista vision and a couple 4 perfs) and they all have the issue. The clamshell is not going down enough, that's the problem. It still works ok, vertical and lateral registration is perfect, issue is the film is not held tight enough so one corner flaps a little bit when playing back footage.

Small update - I talked to Richard Bennett at Cinema Gear and he said it can be adjusted but that once adjusted, Only the movement used during the adjustment will work properly. 

Richard is very busy right now but will get back to me next week. If I could figure it out sooner would be great, some of my scan are a little sloppy because of this. 

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Update: I's fixed! 

Richard guided me through email and I was able to adjust my Vistavision movement pressure.

Here's some information if anyone in the future need to adjust the movement pressure for ACME projector, pretty sure Oxberry works the same way. 

Everything needed is on the CAM block. 

There's a set screw on the side of the cam block, you have to loosen it to adjust the cam block.

Basically there are 2 rings, one behind the cam and another one in the back. The front ring is easily accessible when removing the movement, it's right there.. the one in the back you have to remove the shaft coupler from the back of the CAM block and the ring is there. It's a ring with 2 little holes so you insert a small screw driver and can rotate it. Doesn't look like something you can adjust but once you insert a tool in one of the hole the ring turns very smoothly.  You can now move the cam back and forth, forward increases the pressure  and back loosens it.

Front ring is more like a guide, once you set the pressure needed you turn the ring to set the position and the back ring allows you to move the cam block back and forth. Once everything is set you tighten the set screw on the side of the cam block and that's it.

See image for details.

image001.jpg

Edited by Robino Jones
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  • 4 years later...
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Late to the game here, but thanks for posting this information!

I assume this is very valuable information when bi-packing elements in the projector head.

How did you determine the clamping pressure to be applied by the adjustment and is there a way to measure with a micrometer for repeatability?

Thanks again!

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18 minutes ago, Frank Wylie said:

Late to the game here, but thanks for posting this information!

I assume this is very valuable information when bi-packing elements in the projector head.

How did you determine the clamping pressure to be applied by the adjustment and is there a way to measure with a micrometer for repeatability?

Thanks again!

You could possibly hook a micrometer in the gate opening and place the tip on the cam but moving the cam block is not precise you have to wiggle it a bit to go up and down. My movement was pretty loose and you could visually see the issue by touching on a piece of film in the gate. I moved the cam in one little bit a time and tested until the film was held firm but not too firm. I have to say that after the adjustment was made, all my movements worked perfect in the projector even though I mentioned in previous post that the adjustment would work only with 1 movement..

It's been a couple years I'm a lot more comfortable with these things now, send me a PM maybe I can help you if you have a problem.

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Great information!

I don't have any pressing need for it now, but I am in the process of moving an ACME printer to my house this very weekend to restore it and have always wondered how to adjust the gate for bi-packing material.

Hope you don't mind discussing similar stuff in the future!

 

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