my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Benefits of LaVezzi VKF sprockets?

Author Topic: Benefits of LaVezzi VKF sprockets? Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 08-21-2003 03:52 PM                     Would someone be so kind as to enlighten me? Are they usually available for most Proj/sound heads? Thanks  |  IP: Logged John Pytlak Film God Posts: 9987 From: Rochester, NY 14650-1922 Registered: Jan 2000 posted 08-21-2003 04:04 PM                        Wider sprocket tooth profile "spreads out" any perf stress over a wider area, and the rounded corners reduce stresses in the perforation corners: http://www.lavezzi.com/LavFAQ-VKFII.html http://www.lavezzi.com/VKF.html Originally, the VKF sprockets were designed to be compatible with both KS-1870 perforations and the smaller CS-1870 (CinemaScope used with mag striped film) perforations, but have been redesigned for use with KS-1870 only, since CS-1870 perfs have not been used since the early 1980's.  |  IP: Logged Will Kutler Phenomenal Film Handler Posts: 1506 From: Tucson, AZ, USA Registered: Feb 2001 posted 08-21-2003 04:07 PM                     As quoted form the LaVezzi catalog "Whether driving film, perforated lead frames or in TAB applications, protecting perforations against premature failure is often critical. Thus the form and finish of the VKF (Very Kind To Film) sprocket has been designed to reduce damage to the perforation. The VKF tooth has a maximun width across the flat driving face to minimize the stress on the perforation face. the corners of the teeth have been radiused to clear the perforation radii. This eliminates the potential for damage when lateral motion causes the perforations to slide over a relatively square standard tooth corner." "The finish of the VKF tooth form has been enhanced using the Radii-Blend TM process. With this procedure, every intersecting tooth edge, both at the sides and the top, is blended and burnished to offer a polished surface. This insures a smooth engagement and disengagement of the perforated edge with the tooth surface." "Although the stock VKF design was origonally intended for materials perforated per ANSI-SMPTE 102-1991 or 139-1986, the process may be applied to other tooth forms. Super 16 and 35 , as well as 70mm tooth shapes, have been improved using this procedure. Contact LaVezzi for information on variations of other similar applications." On a side note, I do believe that LaVezzi VKF sprockets are less prone to "hooking". Today, VKF sprockets are almost standard equipment. I do believe that VKF sprockets can be adapted to older projector intermittents such as the Simplex Super and E-7, but applications should be checked with LaVezzi, as they do have the application information/charts.  |  IP: Logged Paul G. Thompson The Weenie Man Posts: 4718 From: Mount Vernon WA USA Registered: Nov 2000 posted 08-21-2003 07:48 PM                     LaVezzi VKF Sprockets are the greatest thing since sliced bread.  |  IP: Logged Dick Prather Master Film Handler Posts: 259 From: Portland, OR, USA Registered: Feb 2002 posted 08-21-2003 08:17 PM                     VKF sprockets are available for most of the common American projectors and soundheads. They do not make a VKF for old style taper pin intermittent sprockets just the updated nut and bolt versions. I use them for all replacements on rebuilds. For normal use they are the best sprocket out there. They also have a newer VKF II sprocket. Check with the LaVezzi web site for info. One problem is that they will NOT run shrunken C/S or Fox perfs. They can damage your shrunken mag film. Since I do run older mag film I took my VKF sprockets out and replaced them all with new C/S ones.  |  IP: Logged Steve Kraus Film God Posts: 4094 From: Chicago, IL, USA Registered: May 2000 posted 08-21-2003 09:28 PM                    Super 16 and 35 , as well as 70mm tooth shapes, have been improved using this procedure. Sprockets specifically for Super 16 or Super 35? Huh?  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 08-21-2003 11:13 PM                     Steve it says Super16 and 35, not super 16 and super35  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-22-2003 10:28 AM                     We recently custom fitted a set of VKF 24 tooth sprockets to a DP-70 for testing. Seems to be runnng really good. This will eliminate the need for expensive 35/70 alumnium sprockets that have short life span. I have yet to see a re-designed 70mm sprocket that has incorporated VKF or Positrol teeth. Something that should be done though....... Mark  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 08-23-2003 02:14 AM                        So does LaVezzi make CS sprockets that are comperable to the VKF configuration? Dick said: Since I do run older mag film I took my VKF sprockets out and replaced them all with new C/S ones. Are these better than what for a better term would be "normal" CS sprockets? Or just new? Didn't I read somewhere that CS sprockets BETTER for film (contrary to what your gut would tell you)? I seem to recall they did wear tests on CS -- foxholes -- prints and regular print film and the CS prints held up better. It stuck in my mind because it is just the opposite of what you would think would be the case. Frank  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-24-2003 09:39 AM                     Frank, You are on the right track but just have it backwards. CS, or Fox holes are actually much stronger than regular KS perfs. However you'd find that use of CS tooth sprockets on KS perf film is not as gentle to the film as a VKF tooth sprocket would be. VKF teeth also generate less film dust due to the wide face and rounded corner teeth. As for Dick removing his VKF's to run CS perf film it is definately not necessary to do this unless the Mag striped film were shrunken laterally. I've run many 35mm mag prints with VKF tooth sprockets without any problems......the VKF teeth were designed to be compatable. On the other hand even all 15/70 projectors I've seen and or run are still using tiny cs style teeth. I'm surprised that none of the LF machines have incorporated that tooth design.....LaVezzi actually makes the Imax projector input and output sprockets anyway. Another point to note...... Don't get Posi-Trol and VKF teeth mixed up. Posi-Trol teeth ARE NOT compatable with CS perfs!! Mark  |  IP: Logged Chris Hipp Phenomenal Film Handler Posts: 1462 From: Mesquite, Tx (east of Dallas) Registered: Jul 2003 posted 08-24-2003 10:48 PM                     Mark: I remember in a recent post you had DFP 2000 sprockets that are hardcoated. Could you either email me the information on those or give me the phone number. I cant find that last post with the info.  |  IP: Logged Dick Prather Master Film Handler Posts: 259 From: Portland, OR, USA Registered: Feb 2002 posted 08-25-2003 12:40 AM                     Mark is correct. VKF sprockets were designed to run fox hole film and they are a better sprocket. Unfortunatly I do have shrunken mag that would not regester properly on my XL 24 tooth sprokets. To not damage the film I put new C/S sprockets in place of them. Frank, The C/S sprockets were just new in the box from stock I had on my shelves. I don't think LaVezzi ever made a C/S VKF sprocket or at least I never saw one. All my films run just fine on the smaller teeth for being quiet and picture quality.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-25-2003 09:42 PM                     Chris, We do have a supply of the Sony sprockets on hand. They are hardcoated to a metal depth of .001, and with a .001 thickness on top of that. This will increase the life of them drastically although I can't predict exactly how much. We have a couple out in the field and have had no problems with them. Give us a call if you need one. They are far less expensive than getting them form Sony and exactly the same sprocket! BTW: These sprockets have the old standard tooth design which is better for wear than a CS tooth alumnium sprocket is. Mark @ CLACO 801-355-1250  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 08-25-2003 10:44 PM                     When we switched to the Hardcoat version of the sprocket, the buzzzzzzzing noise assocaited with the sprocket also vanished too! However, DON'T try to run any CS perfs though that sprocket... the teeth are not centered on the CS perf but on the inside edge of the KS perf (the CS film will buckle) Somwhere I have the drawing on that sprocket...I'll see if I can dig it up. Steve  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.