Graflex.org

[TheCowGod]

Hey guys. I'm hoping you can help me figure out what's wrong with my Kalart rangefinder on my Crown Graphic. There seems to be something disconnected in the internal mechanism. Essentially, moving the arm (that attaches to the post that runs through the body) doesn't move the lower prism at all.

More specifically, I've disassembled it as much as I dare and I see that the arm does seem to have an effect on the "reverse threaded" screw -- moving the arm backwards will move the screw backwards (and thus cause that flat metal piece protruding out of the back of the rangefinder to slide into it), but there seems to be a return spring disconnected or something, because the reverse-threaded screw will only return forward if I tilt the rangefinder unit forward so that gravity pulls it down. This is best demonstrated with this series of pictures (click to see larger ones) :

Rangefinder housing facing upward: screw remains in rearward position, arm has no effect on screw:





Rangefinder housing facing downwards: screw falls forward with gravity, and is pushed back up when the arm is moved backwards. This is how I assume it's supposed to work all the time:





I'm guessing there's something disconnected inside the rangefinder, but I wasn't sure if it was safe to disassemble it any further.

However, there seems to be a second problem. Even when I tilt the rangefinder assembly forward so that gravity is helping the reverse screw move with the arm, it still has no effect on the prism. The arm that the prism is mounted to does move about a millimeter backwards if pushed (and then returns forward due to the small spring on the bottom of the prism). But there doesn't seem to be any connection between the "reverse-spring-and-protruding-metal-piece assembly and the prism assembly. I'm sorry for my terminology

Both problems seem to be occurring within the metal plates that make up the rangefinder. Does anyone have an idea what might be wrong? If the solution is to open it up further, which screws should I undo? It's not obvious to me what I should unscrew next.

BTW, what range of movement should the big arm have? As you can see in the pictures, mine only moves about ten degrees before hitting some kind of internal stop. Is that normal? It doesn't seem like that'd offer much range of focusing. I haven't paid attention specifically to the front standard when focusing, but it seems like it regularly moves out farther than the arm can reach. Is that just a limitation of the rangefinder design, or is it another indication of something awry in the mechanism of mine? Thanks for your help.

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BinaryRock

[TheCowGod]

Aha, I figured it out I got adventurous and pried at the front plate of the RF body until I figured out that it's just the single central screw (next to the front adjustment slider) that is holding it together. Once I undid that screw, I was able to take apart the two halves of the RF and see the mechanism inside. At that point, it was simple to figure out that one of the linkages had rusted and siezed. I undid the screw to break it free, and then turned it a few times and retightened it. Everything now seems to work as it should. Now I get to adjust it as described in many places online. Just figured I'd post the solution in case someone else is trying to figure out how to disassemble a Kalart rangefinder.

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BinaryRock