Film-Tech Forum ARCHIVE: Gaumont-Kalee Model 20

This is topic Gaumont-Kalee Model 20 - Takeup Spoolbox in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Mark T Eccles (Member # 2347) on 04-10-2004, 09:12 AM:

Hello,

I am renovating a GK-20, and have managed to get film running. The picture is fantastic! However, I think I've chained the takeup spoolbox to the soundhead casting incorrectly, because the film is taken up quicker than the projector feeds it out. This subsequently leads to the film snapping. I've tried altering the chain path, and varying the loop sizes, but it doesn't stop the problem.

Could anyone please suggest a solution?

Many Thanks,

Mark [thumbsup]

Posted by Gordon McLeod (Member # 33) on 04-10-2004, 12:42 PM:

Sounds like a takeup clutch issue that needs adjustment

Posted by Howard Johnson (Member # 62) on 04-10-2004, 01:47 PM:

Mark, if it's any help we have a GK20 on display in the foyer of the Dome cinema in Worthing. It's on loan from the projected picture trust. I am working next tuesday and could have a look for you at the take-uo assembly if you contact me.

Posted by Dan Lyons (Member # 1454) on 04-10-2004, 03:01 PM:

quote:
I think I've chained the takeup spoolbox to the soundhead casting incorrectly, because the film is taken up quicker than the projector feeds it out. This subsequently leads to the film snapping

ohh jeez....
please tell me that you're just using junk trailers and such... [uhoh]

Why would you even run film without first using a scale to measure the amount of tension the feed and takeup?

danny

Posted by Mark T Eccles (Member # 2347) on 04-10-2004, 04:52 PM:

Hello,

Thanks very much for the suggestions, guys.

I've varied the tension of the chain, but the problem seems to be with the ratio between the soundhead gearing and the bottom spoolbox gearing, making the takeup too fast for the projector output. The soundhead gearing requires the chain to go through it in a certain way, in order to provide the critical gear-to-gear ratio between itself and the bottom takeup gearing. Unfortunately, there isn't a clutch mechanism installed, so that chain speed is crucial!

Any ideas as to the correct setup would be very gratefully appreciated.

With Kind Regards,

Mark [thumbsup]

Posted by Richard Fowler (Member # 893) on 04-10-2004, 05:36 PM:

Sorry there has to be a clutch to allow for slippage and changing diameter of the take-up roll. The average rpm can average 75 at the hub of a 2000' reel and more like 20 with a full reel.

Posted by Phil Hill (Member # 371) on 04-10-2004, 11:05 PM:

Mark, as a chemist that claims to be interested in technology, try this “experiment” to illustrate Richard’s explanation and post.

Outdoors, on a long straight road, mount a 2000ft reel full of film on a spindle. Have your wife/girlfriend/boyfriend/dog/neighbor/whatever take the end of the film and start running down the road at about 1.03 mph (90fpm).

Notice that as the films is peeled away the reel turns faster and faster...it does NOT turn at a constant speed even though the film is being removed at a constant linear rate.

Thus, SOME sort of “clutch” or variable-speed, constant torque drive is necessary to allow for the changing reel RPM as the film is built on the reel.

Your chain drive is a “hard” constant-speed drive and no amount of fussing with the chain tension will correct your basic problem.. get a clutch...and a grip. [Big Grin]

>>> Phil

Posted by Mark Gulbrandsen (Member # 72) on 04-10-2004, 11:20 PM:

All of the Kalees that I've had down here and came from Canada, some via Gord, were belt drive take up. Many lower spool boxes had magnetic clutches fitted on them. The others had a simple friction type clutch which is the most common type of clutch for feed/takeup spool boxes. Your upper spool box more than likely has a friction type clutch on it and the bottom one ALSO HAS to have a clutch to work properly.

I always thought they were beautifully constructed machines with the fit and finish of a fine watch......

Mark

Posted by Mark T Eccles (Member # 2347) on 04-11-2004, 06:07 AM:

Hello,

Thanks for the advice chaps. At the crack of dawn, I went to investigate the bottom takeup (it was a bit easier to arrange than the road-running experiment, but that did indeed confirm my suspicions!) All your advice pointed to the existence of a clutch, and I'm rather red-faced to admit that after a good twist of the shaft, I discovered there is indeed a clutch there!

My only excuse is that this machine, as you suggested Mark, is so well designed that the clutch is quite well hidden from view! I've only just added this spoolbox, as at the Student Cinema where the projector was previously used, they had a Westrex tower and had attached a simple bracket and roller at the bottom, en route to the tower system.

I'm just amazed, having worked with Victoria 5, 8 and 9 projectors, how steady and crisp the picture is from this old but sturdy workhorse. I'm using a 500 watt halogen floodlamp as the 'lamphouse', which doesn't give a brilliant focussed beam of light at the aperture, but is sufficiently bright nonetheless, gives a good colour temperature, and is cheaper than a xenon!

OK, must now try running some film through it (old stock for starters). Watch this space!

With many thanks for the advice.

Best Wishes,

Mark
[thumbsup]

Posted by Phil Hill (Member # 371) on 04-11-2004, 06:13 AM:

Mark E... [thumbsup]

>>> Phil

Posted by Mark Gulbrandsen (Member # 72) on 04-11-2004, 06:20 AM:

Mark,
Although some techs may disagree I think the Kalee 19, 20, and 21 are some of the finest machines ever made. Perhaps a bit unorthadox to service some pints of the machine, but none the less the build quality from a machinists point of view puts just about every other projector to shame excepting the Phillips stuff. The Kalee is the only projector I've ever seen with a hand scraped mainframe surface.... The fact that they would bother to do that tells me alot....
Enjoy the machine!!!
Mark