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Author Topic: VKF vs. "Fox" sprockets for mag prints Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 02-09-2009 03:21 PM                  Hey yous hardware/film brains out there... I have four 35mm projectors and they all have VKF sprockets. I'm looking to keep one or two of them thar machines for my home screening room and sell off the others. My bottom-line question is: Will the VKF sprocket set work for 35mm 4-track mag prints or should I install my 2 sets of "Fox" sprockets? If the Fox sprockets are required, would they be OK for non-mag "standard films or would I have to play the change-game for each type of print? Thanks!  |  IP: Logged Robert Minichino Master Film Handler Posts: 350 From: Haskell, NJ, USA Registered: Dec 2005 posted 02-09-2009 03:29 PM                        I have no actual experience here, so prefix all of the sentences with "in theory." The VKF (as opposed to VKF-2 or positrol) sprockets will fit into the Fox/CS perfs on unshrunken film, but if the film has shrunk significantly (and for anything with CS perfs this is likely) you'll probably shred some film. The CS sprockets will work fine on normal KS perf film with a little extra stress on the sprocket holes.  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 02-09-2009 03:44 PM                  Thanks for the info, Robert. How can I tell if I have VKF vs. VKF-2/Positrol sprockets? Thanks!  |  IP: Logged Robert Minichino Master Film Handler Posts: 350 From: Haskell, NJ, USA Registered: Dec 2005 posted 02-09-2009 04:59 PM                        Calipers? The Lavezzi site has excellent dimensioned drawings for their sprockets. http://www.lavezzi.com/QA/LavSprocket.html  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-09-2009 05:54 PM                     Phil the positrol will have one tooth set visibly wider than the other, you don't need calipers to tell the difference. I must respectfully disagree with Robert..the VKF's are LESS likely to damage shrunken film..I have some ancient mag stock (a test loop) where the LENGTH has shrunk, but it tracks just fine on VKF equipped machines. In fact, in the literature lavezzi sent out when the VKF series was introduced, one of its selling points was better control and safer handling of shrunken or damaged film.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-09-2009 08:44 PM                     Should be no problem at all and the CS perfs are actually ALOT stronger then KS perfs are. So the use of VKF teeth on CS perfs is actually beneficial. For the sprockets to actually damage film the stock would have to be drastically shrunken and it would be shrunken to the point that it may not even wind on the taske up reel. I had a MAg/Optical print of Sand Pebbles once that was so badly shrunken that the filum wouldn't wind properly on the reel.. but on screen it played reasonably well using VKF's. Mark  |  IP: Logged Dick Prather Master Film Handler Posts: 259 From: Portland, OR, USA Registered: Feb 2002 posted 02-10-2009 03:15 PM                     Phil, The VKF sprockets were designed to run mag film with no problems but I had some shrunken mag that would not run properly on X-L sprockets. I replaced all my VKF sprockets with new CS sprockets and have had no problems since. We ran all film on CS sprockets for years in the theatres. If you have lots of shrunken film I would recommend changing sprockets, Dick  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-10-2009 06:48 PM                     I've heard Phil has a lot of shrinkage...  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 02-10-2009 06:51 PM                     Tony, Thats just from Phil swimming in the Ocean!  |  IP: Logged Jack Theakston Master Film Handler Posts: 411 From: New York, USA Registered: Sep 2007 posted 02-11-2009 08:32 AM                     I've run all of my mag prints on VKF sprockets and never had a problem. They're also quite gentle on shrunken KF/BH perfs, too.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-11-2009 11:36 AM                     We've definitely experienced some VKF sprockets not working with shrunk CS perf prints. Those clients of ours that run 4-track have CS sprockets too (now). Steve  |  IP: Logged Phil Hill I love my cootie bug Posts: 7595 From: Hollywood, CA USA Registered: Mar 2000 posted 02-11-2009 02:00 PM                  Thanks to all for your comments. quote: Steve Guttag Those clients of ours that run 4-track have CS sprockets too (now). Steve, do you mean they have the CS ones permanently installed (even when running non-mag films), or only install them when necessary for mag prints?  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 02-11-2009 04:19 PM                     Yes, they are on all of the time. Steve  |  IP: Logged Stan Gunn Expert Film Handler Posts: 176 From: Clematis, in the hills near Melbourne Australia Registered: Aug 2000 posted 02-13-2009 04:45 AM                        Hi Phil I run alot of nitrate have run much mag and vin/syn.And in all cases find that fox sprockets run the smoothest of all. Stan  |  IP: Logged

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