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Author Topic: Century JJ penthouse coupling Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 11-11-2006 09:44 PM                        I seemed to have misplaced one of these while moving projectors from one theatre to another. I believe that it is Century part # CG-629, but am not sure, as several different styles are listed in the parts manual that I have. This particular one would have been a black cylinder with four small Allen screws to attach the flexible shaft in the penthouse to the one in the projector head. Is this just a standard part, or is it Century-specific? Is there any way to tell definitively what part I need? I have the one that goes with the second projector and could probably post a picture in a week or two if this doesn't get sorted out by then. Also, would it be worthwhile to decouple the penthouse from the rest of the machine when not running mag? It seems like it would save some wear on the mechanism, and re-coupling it wouldn't be terribly difficult, given some advance notice for those once-a-year shows. Thanks.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-12-2006 11:15 AM                     That type of coupling has long been discontinued and replaced with a newer style coupling. It will probably be necessary to get an entire new couping from Strong unless a scrapper machine can be found. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-12-2006 11:44 AM                     quote: Mark Gulbrandsen That type of coupling has long been discontinued and replaced with a newer style coupling. It will probably be necessary to get an entire new couping from Strong unless a scrapper machine can be found. Bzzzzzzt. Wrong. It is a stock item at Wolk and always has been. We stock em too. About all that goes wrong with them is grease/oil seep down into the one on the optical soundhead and it puckers up. The Penthouse one almost never fails. Steve  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 11-12-2006 01:43 PM                        So, did I get the part number right? The parts manual that I have for these machines doesn't have a drawing of it. Is this the same as the coupling between the projector head and the soundhead? It looks similar, but I haven't compared the two closely. Is it worth replacing this with the new style and, if so, is that an expensive conversion? If it helps anyone, these JJs are s/n 513 and 514, which I assume dates them to the mid-1960s.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-12-2006 07:51 PM                     The part number sounds correct...CG-629 or CG-639, I don't recall off the top of my head. As to converting them to the current style...it probably isn't worth the effort, in my opinion. The current version is the best, for sure. You may find though that everything does not measure out the same so you might find yourself changing out vertical shafts too (not in the projector but in the soundheads). If it were me, I would just change the coupling with the same type...especially the penthouse one...it almost never fails. One thing to note is that the penthouse sprocket shaft does not have a means for lubrication (no oil cup and bronze bearing)...so feel free to lubricate that shaft and bearing well before re-activating the mechanism.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-12-2006 09:09 PM                        If you do change to the new style coupling, I believe that the old shaft will work if shortened. (hack saw or equal.) This is certainly true of the lower coupling. Louis  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-13-2006 06:36 AM                     quote: Steve Guttag Bzzzzzzt. Wrong. Actually Bzzzzzzt right... ORC discontinued that form of coupling way-way back and for good reasons. The new coupling is quite superior at mechanical isolation to the old straight couplings and the new is pretty pricy too. The old one is obsolete and making obsolete partsn for obsolete equipment is Wolks #1 specialty.... because they have it doesn't mean its not obsolete! If you decide to use older obsolete parts in your customers equipment thats your buisness but the last JJ I rebuilt got both new style couplings installed. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-14-2006 10:13 AM                     No Mark you were wrong and remain wrong. It is not obsolete...just not carried by Strong...they work just fine too. Again, the only real issue with them is when the various lubricants wick down from the projector and get into the rubber coupling. Compared to the service life of belts and such...they are entirely adequate without having to spend the money on entire new assemblies/couplings or doing extensive shaft modifications. Face it. You gave a wrong answer...you didn't say that while the older design part is available, you'd be better served by updating it to the current part....you said it was effectively gone, which it is not.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-14-2006 05:42 PM                     Steve, You can disagree till the sky turns green if ya want to. When a manufacturer discontinues the use of a part in favor of a better part that improves performance then in my book that older part is obsolete. There are companies that manufacture new parts for Model-T's but you don't still drive one do you? If you choose to use the old version of the coupler thats fine but I prefer to use the part that gives superior performance when I can... In this case the spiral cut in the coupling serves to aid in isolating the machanical vibrations that the projection mechanism generates. So if ya want lower flutter spec I guess you'd use the new part too. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-15-2006 08:22 AM                     It is not a matter of disagreeing...what you said was WRONG. You gave the impression the part was not available when in fact it is. So what if ORC stopped issuing the part...they stopped issuing the whole line of projectors too...perhaps Century is just obsolete and one should just throw them away and put in the current stuff...ya know, DCinema...that too would lower the flutter spec. It would also be consistant with the posts you make. I, for one, have not had massive issues with flutter using the rubber coupling...I guess you have. You are more apt to have flutter issues from the bearings not being well seated in the frame...a problem Component Engineering solved. As to Model-Ts...nope, I don't drive em but Model-As yes. The T doesn't go fast enough for today's roads. The Model-A can keep up though it doesn't do too well on uphills at highway speeds. Steve  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-15-2006 09:53 AM                     Thats ok Steve.... you go ahead and use the old part.... I'll go ahead and use the later version and squeeze a little better performance out of the thing..... Thats all it amounts to... And yes, I will happily embrace the new systems... it is what the future will be. Mark  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-15-2006 02:12 PM                     quote: Mark Gulbrandsen a little better performance out of the thing Not too likely. I too embrace technology...I just like to get something better than what I have out of it. My 35mm film systems are generally getting about double the resolution of a 2K DCinema system, JPEG or no. In fact, it is easy to see when 2K intermediates were used.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 11-15-2006 06:49 PM                     Actually the whole design interntion of that type of coupling is to isolate the source and driven member from each other... something that can't be taken too lightly in a mechanism like the JJ... any improvement is a benefit! There were measurable flutter differences done at ORC years back when that coupling came to be. One disadvantage is that its pretty expensive. As for digital it is very definately lower resolution... something we will all be more or less forced to live with for quite some time to come. On a common 30 foot wide screen its not actually all that bad and can actually look better than most of todays film presentations. If it was anyone else but Sony doing the 4K thing I would say it will fly and go places but unfortunately its the wrong manufacturer and it'll go no where!! No one is going to take Sony seriously after the SDDS debacle. They've done very similar things to the broadcast industry as well. And to boot Sony is not a healthy company. Never the less those of us that fail to embrace what is about to happen will be left with their heads burried on the sand. Mark  |  IP: Logged

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