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How It Works
Shutter Winding Mechanism


Here's the take-up spool assembly. Not much to it. The gear engages the advance gear train and the spring on the shaft is the business end of things that drives the fork. The pronged fork slips on the shaft between the spring and the washer/screw on the end of the shaft.


Starting at the winding knob working our way down, #1 There is a gear under where the winding knob attaches, trust me it's really there. #2 and #3 idler gears. #4 gear is on a shaft #5 which has a pin that engages through to the advance sprocket.


Turn the assembly over and we see shaft #5 sticking through with gear #6 attached to the same shaft. This engages #7 gear which actually is the brake which prevents the reversal of direction of winding. You can't really see it but there is a couple of tabs #7a which rotates freely when the winding direction is the right way but when you try to reverse one of the tabs jams between the gear teeth. Kind of barbaric but it works. Gear #7 then mates with the take-up spool gear head #8 in next image.


 Hear the take-up spool gear #8 in position on the casting body.


Here's a side view of the complete assembly in place that offers a different perspective. Again the same sequential numbering from the winding knob #1 to through to the take-up fork #8. Don't mind the tweezers with the washer in this image. I was using this to remind myself that this washer goes under the brake gear #7.

Pretty simple huh? Yes, but seemingly complicated when one has issues with spacing problems of images on a negative. What can go wrong? Referring to the above image we find a whole lot of gears that have a certain amount of backlash. Added to this the spring and the washer/screw tension that allows the pronged fork in the first image at the top to slip is very critical. What should the proper spring tension or pronged fork torque slip be? Good question, but it does influence whether the pronged fork is pulling the film off of the advance sprocket or the film is being pushed.


June 24, 2007