Repairing your camera
Most Kodak cameras were sold in large quantities and therefore had to be produced very cheaply. When Eastman built his first commercial camera in the 1880s it proved to be too difficult to mass produce a high quality camera for a small price. This camera therefore did not make it to the market in reasonable quantities. Eastman learnt from this experience and decided the camera mechanics had to be simplified in order to decrease the number of steps necessary during the manufacturing process. The second camera therefore had a simplified shutter, making the camera easier and cheaper to produce.
This makes for the fact that it's often very easy to repair and service the basic Kodak cameras. Box cameras can easily be taken apart, cleaner and put back together. Just be careful to remember how you took it apart and you'll be fine most of the time. The viewfinders are often dirty but when you're careful you might be able to open them by bending a few metal clips and clean the metal "mirror".
Folding cameras might be a little more tricky to take apart. To save costs, the bellows were often of lesser quality and have sometimes fallen apart, or spot numerous holes. Smaller holes are easily repaired using some tape or putty leaving the bellows in place, this is however a temporary solution, the repair might fall off or new holes might develop, and you'll only notice when you have developed the film. When you have enough patience, you might be able to fold a new bellows for the camera. Sometimes bellows were glued to the camera, making it difficult to separate them from the camera frame without bending other parts of the camera. So before you start making new bellows, make sure you know how to remove the old, and put on the new bellows.
The more difficult Kodak cameras to repair are the German built Nagel Kamerawerke / Kodak AG cameras such as the Retina, Retinette and Duo-620 series. Although these were, for 1930s German camera standards, relatively simple cameras, they are the better Kodak cameras, mechanically more sound and therefore working more precisely. My 1958 built Retina 2C works like new and really does not show it's age of 50 years.
Range finders might get out of alignment. Basically the system is not too difficult to understand but since range finders where often put in tiny places on the camera, it's often hard to find how to adjust them.
Where to start
The best way to start repairing your classic cameras is to buy good quality tools. Forget about the cheap watchmaker's screwdriver sets, they bend or break easily, buying small good quality screwdrivers is only marginally more expensive and makes the repair process a lot easier.
Take an easy broken or dirty camera first. Take it apart, watch how things work, clean it and put it back together again. The first camera I worked on was a simple Kodak No. 2 box camera and it's great to be able to figure out how it works by just looking at it. The shutter is nothing more than a small spring pushing a larger disc past the lens opening. The spring tension and the shutter weight control the shutter speed.
Cleaning the lens is easiest using pure alcohol and cotton swabs. Make sure you're not moving any crud around scratching the glass. The big advantage on working on a box camera is that when you break it or can't get it back together or can't get it back to work, you don't have to worry too much, most Kodak box camera types are abundant so you can always get a new one and start all over again. :o)
Books on Camera Repair
When you want to learn the basics of camera repair, it's advisable to refer to the camera repair books by Thomas Tomosy. He describes the basic techniques of camera repair and shows how to repair a large selection of cameras. When you're camera is not listet, there's always another one described that look, or at least works, similar to yours. The books are great and also shows the tools you'll need and gives tips on how to make your own tools.
When you're familiar with the basics of camera repair, you can always look on the web for tips on how to repair your camera or ask for information in one of the many camera forums.