Kodak Ball Bearing Shutter

The Kodak Ball Bearing shutter was used on a variety of early Kodak cameras such as the Autographic folders. The shutter shown here was taken from an Autographic Junior A-120.

These shutters are simple shutters that rely on spring tension for speed control. Typically, this type of speed control is inaccurate due to loss of spring tension. There isn't much you can do to adjust the speeds if they are wrong. Although you could try bending the end of the spring slightly, on springs this old that may not be a good idea. However, if you measure the actual speeds with a shutter tester, you can then calculate a good exposure from the actual speed. When I tested this shutter the 100 setting produced a speed of 1/50 sec. The 50 and 25 settings were nearly identical at about 1/30 sec.

Unscrew the lens cells from the front and rear.

Remove the two screws in the plate over the speed setting lever and remove the plate. Remove the two screws in the aperture indicator and remove the indicator plate. Lift out the aperture setting ring.

Turn the shutter over and remove the three screws around the outer edge. The shutter cover can then be lifted off. You may need to pry the cover slightly to get it off.

With the cover off, you can reach all of the mechanism. All of the parts come out from the front. To get to the shutter blades you have to remove all the parts. You can flush clean any sticky parts at this point and may not need to do any more disassembly.

Push the speed setting lever clockwise to the 100 setting. Remove the spring on the T/B lever and then pull the bottom part of the lever down until the top part rotates clear of the speed lever. You can then lift the T/B lever out.

Push the speed setting lever back to the 25 setting, then unhook the mainspring. Note how the blade closing spring is hooked over the mainspring. Unhook the spring that goes over the main activatnig arm. Carefully lift the main activating arm and main spring out.

Remove the screw in the inertia weight and lift the weight off. Carefully unhook the blade closing spring from the blade operating lever and then slide the connecting wire off the end of the spring.

Remove the screw in the base of the speed setting lever and lift the lever off.

Remove the screw in the blade closing spring and lift the spring out.

Unhook the spring on the trigger and lift the trigger out.

Remove the screws holding the diaphragm and lift out the diaphragm control ring. The diaphram wings are permanently attached to the inner base.

Remove the screws holding the inner base and lift the base out.

With the base out you have access to the shutter blades. Note the orientation of the blades before removing them. I found six blades in this shutter. This was commonly done to add balance to the shutter. Two of the blades sit on the same stud.

The blade operating ring can probably be cleaned in place. I wanted to remove it in order to polish the oxidation that was built up on the ring.

Turn the shutter over and remove the four screws holding the lens tube to the shutter base. Lift the tube off. Underneath you find four ball bearings and four roller bearings. This is why it is called a ball bearing shutter! Remove the bearings and the blade operating ring will come out.