All bolex 8mm cameras are spring wound. The torque from the spring motor drives an intermediate gear which in turn drives a vertical shaft that interfaces with the speed regulator and the claw mechanism. If you have a Bolex 8mm camera, there is one of these gears inside your camera. You want to repair the camera? You need to do a few things first or you will have a intermediate gear problem. Here's why...
The first step to repair any spring wound camera is to 'run the motor down'. This means to press the run button until the camera motor stops turning. Not sure? Button doesn't start the camera?
Older cameras are lubricated with both oil and grease. After 50+ years of storage, the grease can harden. The hardened grease can prevent the motor from working. Solution? Remove and re-lubricate. To do this you need to disassemble the camera. This is where the intermediate gear can get damaged.
If you fail to run the motor down properly, the remaining spring tension will still be applying torque to the drive gears. Not knowing this, you remove the 5 screws holding down the cameras top plate and remove the plate. You see the insides of the camera. The gears, regulator, the spring motor, etc. You think, "All I need to do is to oil or grease them!"
They are still filthy dirty so they should be cleaned. You figure this out too and look over the camera. You find the 4 screws holding down the shutter assembly. You accurately conclude that removing the 4 screws will allow you to remove the shutter assembly and further disassemble the camera. So out comes the screwdriver and you take out the 4 screws.
Pleased that you are saving money by doing it yourself, you carefully pull off the shutter.
You look inside and see all the teeth of the intermediate gear fully stripped off. Oops! The spring motor supplied the torque. The only thing keeping the spring motor's gear from turning was the shutter and you disconnected that when you removed it. The springs motor forced the intermediate gear to turn at "light speed" and during the rapid unwind, the bakelite (plastic) gear teeth grazed another metal gear. This sheared off all those teeth.
You now need another intermediate gear :( You may need another spring motor, too - Whaaaaaa!!!! Spring motors do NOT like to go from wound to unwound in less than a split second. It can damage the internal flat spring when it hits the end stop.
Need replacements parts? Bolexrepair.com has them.
Next time - run the motor down :)