Film-Tech Forum ARCHIVE: Century JJ shutter assembly variations

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Posted by Dan Lyons (Member # 1454) on 10-11-2005, 05:12 PM:

Below is a photo of the gear side of my JJ-2STA,#767, single shutter version, as discussed on the last page of the manual "Century JJ-2 and JJ-3 parts manual".

Why on earth did Century choose to run the shutter on this machine with the double shutter assembly? Doing that just throws another pair of gears into things. As you can see, there is no place on the main casting for a front shutter shaft bracket to even go (BR-186). Area circled in red.

The last page of the manual which discusses the JJ-2S talks about omitting the double shutter assembly and using the single shutter shaft assembly, so it would look similar to any other single shutter Century inside, exactly opposite of how they made my machine.

[Confused]

Posted by Steve Scott (Member # 630) on 10-11-2005, 06:21 PM:

I always thought the Century model coding meant the JJ was only a double shutter machine? Is a different shutter used in its place?

Posted by Steve Guttag (Member # 268) on 10-11-2005, 08:01 PM:

Steve, you are correct...original Century naming would mean that "JJ" is a double shutter version of the "J" projector. However, that naming went out the window when the SA and DA machines came out to replace the H and HH.

The JJ2-S (single shutter) is a much later machine...I want to say it came out in the mid 1980s. I remember that the turreted SAs in that era used a shortened shutter shaft whos part number had an "X" on its name to denote it was short.

I don't recall the JJ with the turret not having the second shutter. In short, I don't have the answer to Dan's question handy.

As to JJ shutters...there have been several...the original ones were heavy steel ones...later ones were made of aluminum and have a "V" shape to them. The JJ-2S shuter had a unique number and was to be not less than 90-degrees (standard SA shutters are around 84 degrees and are noted for ghosting...optional SA shutters are 90 degrees (C1-D-48).

However, sometime ago the special single bladed JJ shutter vanished from the various parts lists. The Blade that is part of the C1-D-48 is listed as the current part...problem is, I don't think it has a large enough diameter to work with 70mm film.

There is also the little known C1-D-50S...it is a 100 degree blade (thin steel) and shouldn't have shutter ghosting on 70mm though being a "C" desination is also probably too small a diameter for 70mm. Any proper assembly for a JJ that is unique to the JJ projector, like the shutter should have a "J" series part number not "C" or "H".

Posted by Mark Gulbrandsen (Member # 72) on 10-12-2005, 08:46 AM:

The best shutters made by Century were the Cinerama shutters that were spring loaded and the blade drive was essentially transfered through a series of 4 springs that alloowed the blade to float. The next best were the thick steel shutter blades that you might find on the older JJ'S that are under serial number 500. Lonnie Jenninngs always felt that after about sn 500 the JJ's went to crap and from what I've seen on all the ones I've rebuilt with numbers higher(and lower) than 500 he is definately correct.

Mark

Posted by Louis Bornwasser (Member # 3063) on 10-12-2005, 09:16 AM:

Hadden Theatre Supply, Louisville Ky manufactures a Century shutter assembly that mounts like yours does. The bearings have been changed to a dual-race, much heavier design. This is, however, only used in single-shutter configuration.

The original intent was to get better bearings than the BG-9 and also "work around" the extreme out of squarensss that many Century's (old and new) have in the shutter area. In other words, the shutter shaft is forced out of true in many machines. Shimming cannot always be accomplished in enough dimensions. Louis

Posted by Mark Gulbrandsen (Member # 72) on 10-14-2005, 09:09 PM:

quote: Louis Bornwasser
Hadden Theatre Supply, Louisville Ky manufactures a Century shutter assembly that mounts like yours does. The bearings have been changed to a dual-race, much heavier design. This is, however, only used in single-shutter configuration.

Hey Louis,
Can you please post a photo of that... I might be interested in a few of those.

Mark @ CLACO

Posted by Steve Guttag (Member # 268) on 10-15-2005, 07:40 AM:

Update: I have been able to lay my hands on an original single shutter blade assy for the JJ-2S. It is indeed a 100-degree blade with a diameter of 12-13/32" instead of the 11-3/4" as used for C and SA/DA machines. The JJ blade is also steel instead of the aluminum as used on 35mm machines.

Posted by Mark Gulbrandsen (Member # 72) on 10-15-2005, 08:27 AM:

Yea Steve, thets the good blade... often imitated but for some odd reason never duplicated... The flywheel effect of that blade has a very nice effect on smoothing out the machine. There were also steel double shutter blades as well. I've had machines in the past with both versions of the steel blades.

Mark

Posted by Brad Miller (Member # 2) on 10-15-2005, 04:41 PM:

Everyone, what about 3 bladed shutters for the JJ? I tried a loaner shutter from Steve and love it, but I am looking for a pair that has a large enough diameter to be able to run 70mm as well as one with wider blades, as I am experiencing shutter ghosting at the top and bottom of the image.

Posted by Dan Lyons (Member # 1454) on 10-15-2005, 05:27 PM:

I thought about doing a 3 blade, however I don't think that will work for me. I get minor ghosting on top and bottom no matter how I adjust the shutter knob. Is that from the large amount of play in the shutter due to the extra set of gears involved. [Confused]

Would a 3-blade make my ghosting issue worse, or have no effect?

Posted by Mark Gulbrandsen (Member # 72) on 10-15-2005, 05:55 PM:

3 blade shutters for a JJ would have to be custom made. Talk to Don or Rob at Wolk as they will custom make them for you. This is also a good opportunity to make them out of heavy steel like the originals were made

Mark

Posted by Steve Guttag (Member # 268) on 10-15-2005, 08:21 PM:

The 3-wing shutter I sent you (Brad) was also custom made...it has 90-degree blades and works just fine on 35mm machines. Note, Brad also wants to run at really high light levels (greater than 22fL).

I would think the 90-degree blade would work as a double shutter for the JJ if the diameter was correct.

Posted by Tim Reed (Member # 137) on 10-15-2005, 09:40 PM:

Mark, the Hadden Century shutter assemblies are the cat's meow. This unit was in development when I worked there, and I couldn't wait to see them hit the market. Install it, and never worry about shutter bearings again.
[thumbsup]

Posted by Mark Gulbrandsen (Member # 72) on 10-15-2005, 09:53 PM:

Tim, Good....I have just the location for them too!!

Mark

Posted by Brad Miller (Member # 2) on 10-16-2005, 04:03 PM:

Steve, don't suppose you have another one of those custom 3 bladed shutters I could try using as a double to verify blade width?

I wonder, was there ever a high speed intermittent made for the JJ?

Posted by Steve Guttag (Member # 268) on 10-16-2005, 05:24 PM:

Yeah, there is another one kicking around.

Posted by Mark Gulbrandsen (Member # 72) on 10-17-2005, 07:57 PM:

quote: Brad Miller
I wonder, was there ever a high speed intermittent made for the JJ?

No, but the Cinemascope 55 machines had movements that were slightly accelerated but not to the extent of the X-L movement. The cam pin was mounted to a sliding dovetail which was part of the cam. The dovetail was moved by a roller underneath the cam that ran in a machined groove...... As the cam went around the dovetail moved slightly. Remember that the CS 55 frames were pretty tall! I gave one of these movements to the Chicago Cinema Museum quite a few years ago, so there is still one of this type around in existance. They would probably let you examine it if you're ever in Chicago.

Mark

Posted by John Pytlak (Member # 331) on 10-17-2005, 08:56 PM:

If anyone wants to license the "Quickermittent" design from Kodak, I'll put you in touch with the right people. Up to a 27% faster index time (more light efficiency) with no extra parts, just a redesigned profile for the starwheel slots.

Kodak "Quickermittent" Patent PN/6,183,087

quote:
United States Patent 6,183,087
Kirkpatrick , et al. February 6, 2001
Geneva mechanism and motion picture projector using same

Abstract

A driving mechanism such as a Geneva Mechanism which allows a load, such as film in a motion picture projector, to be intermittently advanced with controlled acceleration. The Geneva Mechanism includes a star wheel and a rotating driver. The star wheel includes slots and is operationally associated with the load. The rotating driver includes a drive pin which cooperates with the slots to cause an intermittent rotation of the star wheel. Either the slots or the drive pin is shaped in a controlled manner to permit optimum acceleration and deceleration of the star wheel.
Inventors: Kirkpatrick; David H. (Rochester, NY); Kurtz; Andrew F. (Rochester, NY)
Assignee: Eastman Kodak Company (Rochester, NY)
Appl. No.: 329841
Filed: June 11, 1999