Some older Speed Graphics are found with a very early version of the Kalart rangefinder which requires a somewhat different adjustment procedure than the later models.
The early model can be identified by its metallic finish and the external adjustment scales. The actuating arm and coupling is different than later models. The internal cam mechanism can be reached for cleaning by removing the rangefinder from the camera and removing two screws on the underside of the body. This will allow removal of the bottom cover plate. The cams and levers inside can be cleaned with a suitable degreasing solvent like lighter fluid (naphtha) Ronsonol brand works well. The contacting surfaces should then be very lightly lubricated with light oil. Old rangefinders are often sticky due to congealed grease on these surfaces.
The rangefinder has four adjustments.
You will need to make a small wrench for the actuating shaft. This is simply a piece of thick shim stock with a slot cut in it to fit the flat on the shaft so you can turn it.
Using the wrench turn the shaft to is maximum clockwise position and check to see that the rangefinder goes just slightly beyond the infinity position. If it doesn't loosen the hex head screw and adjust it until it does.
The actuating arm and coupling for this rangefinder is different than used for later Kalarts on Speed Graphics except for the arrangement on the Miniature Speed Graphic, which is similar.
The arm has two infinity adjustments. One is a screw in a spring loaded dog-leg in the middle of the arm. The other is a slider on the camera bed where the end of the arm coupling is contacted. The slider is the coarse adjustment, the screw is the fine adjustment. At the start the slider should be midway in its slots and the adjustment screw about midway in its range.
Using the wrench set the rangefinder actuating shaft to its rearmost stop. Push the actuating arm against the back of the camera and tighten the set screws. Note that drift in rangefinder setting is often caused by loose set screws on the actuating lever collar, they need to be tight. Replace the screws if they are worn.
Once the arm is set the camera should be focused carefully on infinity (a target at least one-half mile away). If necessary adjust the infinity stops. The older cameras on which these rangefinders are used often do not have adjustable focus scales. The lens and scale should agree at infinity focus.
Set the lateral coincidence adjustment at this time. Its locked with two screws. Loosen the screws and carefully turn the plate. A very small adjustment makes a large difference in the coincidence. Once set lock down the screws and continue.
Set the sliders at their approximate position. For 135mm lenses the scales should be set at:
For 150 mm or 152 mm lenses the initial slider settings are:
Check that the rangefinder indicates agreement with the ground glass at infinity.
Then set the camera up at four feet from a flat target. Make a target with separate focusing targets for lens and rangefinder. The target is drawn so that both targets are on the center line of the lens they are to be used with. This is to eliminate parallax which can make this adjustment impossible.
With the camera set up at four feet adjust the front slider for coincidence. Then check the 15 foot adjustment. Readjust if necessary. If the 15 foot adjustment is changed check at infinity again. The three adjustments are somewhat interactive so all three must be checked after any is changed.
Repeat the adjustments at all three distances until all show coincidence with the ground glass image.
These rangefinders are quite stable so this procedure is necessary only when setting up the first time.
The round windows of these rangefinders can be unscrewed for cleaning. This will also allow access to the mirror surfaces. Both should be cleaned with lens cleaner. The mirrors can be accessed with cotton swabs for cleaning. The lower window has a mask in it which can fall out and get lost. Remove it for cleaning and replace it. Use a bit of sticky tape or a bit of rubber glove as a gripper to remove the windows. All three come off.
The outer case does not come off in any simple way, it should be left alone.
Again, these are very approximate initial settings.
A caution:The sliders are locked with screws in the sliding portion. Be very careful not to loosen the screws holding the scales themselves. If they are moved it will make initial settings very difficult.