8mm Forum: Elmo ST 600 Supply arm not moving

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Topic: Elmo ST 600 Supply arm not moving

Mike Piso
Junior
Posts: 2
From: Boston, MA, USA
Registered: Nov 2015

posted November 17, 2015 06:32 PM

Hi,

I recently replaced the belts for an Elmo ST 600 projector and the take up reel and shutter sound like the right speed but when I attempted to load film realized that the supply arm did not want to move and would not move when I put it in reverse. I quick look inside showed that one of the gears will not move. Pictured below it is the second gear from the top left corner and there are two cogs, the one on the outside moves but the one on the inside which should move the one connected to the supply arm stays still. Any suggestions? Thanks in advance

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MP

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted November 20, 2015 12:13 PM

Welcome to the 8mm Forum, Mike!

I believe those two gears have the clutch for the front spindle between them. There should be a cork pad in between them to produce just enough friction and resting torque to rewind a full 600 foot reel, yet nowhere near enough to break a film. (It is adjustable.)

I wonder if your cork has dried up and flaked away or maybe the adjustment has somehow been backed way off.

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All I ask is a wide screen and a projector to light her by...

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Mike Piso
Junior
Posts: 2
From: Boston, MA, USA
Registered: Nov 2015

posted November 20, 2015 09:49 PM

Thanks Steve! I just checked and the cork is definitely still there and comparing it to the cork disk on the take up arm I'm thinking it is pretty much intact. Any idea how to adjust these gears and what to use to oil them?

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MP

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John Hermes
Expert Film Handler

Posts: 139
From: La Mesa, CA, USA
Registered: Nov 2008

posted November 21, 2015 12:01 AM

From time to time, I will remove the gear assembly with the cork, take it apart and clean it. I use Super Lube synthetic grease on the cork and gear teeth and maybe a drop of oil on the shaft. You need to remove the nut and unscrew the spring plate, spring, and gears. Lay them out in the order they came off. After you clean and lube the cork, reassemble the parts. The spring tip fits in a hole in the plate.

As you turn the plate on the threaded shaft, it increases the clutch tension by tightening the spring inward. It is a bit of trial and error getting the right tension. See how far it is screwed in before you disassemble it. The locking nut may have come loose and the plate became screwed in too far, causing too much clutch tension. I happened to me once. Once you get a good tension, tighten the locking nut on the outside against the plate. I use a crescent wrench to hold the plate while I tighten the nut with a metric nut driver. Good luck. It's not too hard once you do it a couple times. The take-up reel adjustment in similar.

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John Hermes

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted November 21, 2015 02:50 AM

John, why would you feel the need to lubricate the cork friction disc with synthetic grease?

Surely this would have the same effect as allowing engine oil to land on your car's clutch friction plate, wouldn't it?

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"C'mon Baggy..Get with the beat"

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John Hermes
Expert Film Handler

Posts: 139
From: La Mesa, CA, USA
Registered: Nov 2008

posted November 21, 2015 12:29 PM

"John, why would you feel the need to lubricate the cork friction disc with synthetic grease?

Surely this would have the same effect as allowing engine oil to land on your car's clutch friction plate, wouldn't it?"

Hello Andrew. I only put a very thin coat of grease, just enough to make the clutch grip nice and smooth. I have been doing transfers with Elmo projectors (ST180 & ST-600 models) since 1986 and this has worked well for me. I always clean the cork with naphtha when I disassemble it as well.

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John Hermes

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted November 21, 2015 12:42 PM

It's kind of a gray area: all clutches are actually supposed to slip, sometimes but not all the time.

The tricky part is manipulating the torque level where they break loose.

I'm glad somebody else took this one. I've never had this problem so I'm not completely qualified to answer the question!

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

posted November 21, 2015 02:18 PM

I have to say on any clutches on any PJ I've ever owned, I've never felt the need to place any kind of lubricant anywhere near the friction parts.
Typically it is wear that is the issue with them and therefore more torque that I find is required by way of adjustments or replacement linings.

One way (Formsprag type) clutches, are of course, a different matter, and should therefore, be treated in exactly the same manner as an ordinary Roller or Ball Bearing where lubricant is concerned.

[ November 22, 2015, 02:37 AM: Message edited by: Andrew Woodcock ]

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"C'mon Baggy..Get with the beat"

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