peter_lerro Posted November 1, 2007 Share Posted November 1, 2007 I recently acquired a Kodak Chevron (with a lens code of 1953.) Although the Synchro Rapid 800 shutter fires at all speeds, there a intermittent lag between when the shutter release is pressed and when the shutter fires. Also, the shutter speeds seem somewhat slow (although I haven't been able to test it as yet.) Before incurring the cost of an expensive overhaul, I thought that I would simply give the shutter naphtha flush. However, before I do this I want to remove the front and rear lens assemblies. Now the front one unscrews very easily, but its not apparent to me just how the rear assembly might be removed through the film cavity. Does any know if this rear assembly can be removed from this vantage, or am I faced with a major camera disassembly project? Pete Lerro PS: just an aside - I also own a Kodak Tourist (with a lens code of 1948)and it has the same type of Synchro Rapid 800 shutter. Now I was aware the Chevron shutters do not age very well, but I'm somewhat puzzled since the Tourist's shutter, although five years older, does not exhibit any of the problems which I experience with the Chevron's shutter. (However, here too, I haven't been able to test the Tourist as yet.) PPS: Does anybody out there know where one can acquire a used Calumet Shutter tester? Link to comment Share on other sites More sharing options...
walter_degroot Posted November 1, 2007 Share Posted November 1, 2007 I saw one of each back in the 1960's the tourist was sold before I could get the cash, later the chevron, the 620 and the reputation of the shutter turned me off as I had read up on that shutter by then. Is it true that the blades rotate 360 degrees rather than opening and closing 180 degrees like a compur shutter. Kodak shutters are not considered to be wonderful I have 2 pony's and 2 signets. that seem to work ok. Link to comment Share on other sites More sharing options...
peter_lerro Posted November 2, 2007 Author Share Posted November 2, 2007 Walter, the shutter blades do rotate, but not 360 degrees. It is actually a case of their first rotating 180 degrees in one direction and then returning to their starting point by rotating 180 degrees in the reverse direction. To understand the operation of the Kodak Synchro-rapid 800 Shutter, it is essential that you understand two key points about its design. The first is that the entire shutter assembly really consists of two shutters: a main, five-bladed assembly, which is the forward-most of the two, and a simpler, two bladed secondary assembly, which is located behind the "main" assembly, i.e., closer to the film plane. The second point to understand is that the blades of the main shutter assembly actually pivot, i.e., they rotate, about their midpoint. (See http://www.prairienet.org/b-wallen/BN_Photo/SynchRapid.htm for an excellent illustration of this feature.) With these two points in mind, here is the simplest explanation which I can offer as to the operation of the Synchro-rapid 800 Shutter: immediately prior to cocking the shutter, the "main" shutter blades are, of course, arranged in their "closed" position, as are also the "secondary" shutter blades. Then, as the cocking lever is moved to its "set" position, the "main" shutter blades rotate through 180 degrees. Of course, after the blades complete this rotation, they once again appear to be in a "closed" formation (this is due to the fact that the blades have just been rotated about their midpoint). However, it's important to realize that mid-way through that rotation, there is a period of time when the blades are fully open. (This entire cycle of the shutter blade motion, which occurs when the cocking lever is "set", is readily visible through the front lens assembly.) Because the "main" shutter blades are open during a portion of the cocking process, light could have had the opportunity to pass through that opening and expose the film if it was not for the presence of the "secondary" shutter, which is designed to remain closed throughout the cocking process. When the shutter release is eventually depressed, it triggers the following sequence of events: 1) the secondary shutter opens, and 2) the main shutter blades rotate back, i.e., they return to their original position. It is during their return motion, mid-way through their reverse rotation, that the main shutter blades are open for a period of time that is dictated by the shutter's speed-dial setting. It is during this period of time that light is finally permitted to expose the film. Only after the conclusion of those two events does the secondary shutter finally close. Link to comment Share on other sites More sharing options...
mark_sampson Posted November 14, 2007 Share Posted November 14, 2007 Which explains why SK Grimes could not repair the Chevron I had a few years back. What a mechanical nightmare! Link to comment Share on other sites More sharing options...
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