After thoroughly scrutinizing how the Super8 Camera and Cartridge operate, I have determined the only possible cause of jitteriness. Contrary to popular belief, it is not related to the Cartridge. It is possible for stiff Film in the Cartridge to cause some problems -- in particular jamming, but not the general problem with jitteriness. Very simply, the cause of jitteriness is the Camera's Clutch. In a Movie Camera, the Take-up Reel / Spool regularly runs out of slack Film as it "takes up" the used Film coming down from the Film Gate. Every time the Take-up Spool in the Super8 Cartridge runs out of slack Film, the Clutch on the Camera turning the Cartridge Clutch has to slip until more Film is pushed down by the Film Gate's Sprocket Arm / Claw. However, if the Clutch slippage is too tight, the Film will be tugged by the Spool -- thus pulling the Film in the Film Gate and causing a jittery picture. The Take-up Spool is only supposed to wind up the Film as it enters the Take-up Chamber. It is the Sprocket Arm which is supposed to move the Film through the Cartridge -- one Frame at a time. In addition to jitteriness, a tight Clutch will also put strain on the Camera's Motor causing it to slow down -- thus screwing up the Film timing! A tight Clutch will also put a strain on the Camera's Gears which can cause damage.
It is very easy to test the slippage strength of the Camera Clutch. You test it with the Camera on and the Cartridge Chamber Door open. Just stop the Clutch with your finger as it turns, and note how much force is required to stop it from turning. It should slip with only a little bit more force than is required to turn the Cartridge's Clutch. In order to appreciate the small force required to turn the Cartridge Clutch, use your baby finger to turn one of the two
blades on the Clutch counter-clockwise a few turns and then clockwise. Only do this on a used or partly-used Cartridge -- not a new one! You will quickly feel when the slack Film runs out, and thus easily determine how little force is required to turn the Cartridge Clutch before the Camera Clutch needs to slip. It's a small amount of force.
The pictures below show the front, side and back views of two types of Camera Clutches from an Argus and Sankyo.
Argus Clutch
The Clutch assembly consists of a Clutch & Shaft, a Gear, a Spring, a Washer and a Locking Ring. The Ring slips into the groove on the Shaft which holds the Washer in place. The Spring applies pressure between the Gear and Washer which causes the Shaft to turn with the Gear. The point of slippage for the Clutch is at the Washer. The length of the Spring is what determines how tight the Clutch is before slipping. If this Spring applies too much pressure you thus suffer jitteriness. The Spring you see in the center view picture is less than one-half of its original length! The Clutch on this Camera was originally way way too tight! It now slips properly. With the cover off of the Camera, you can test the Clutch's slippage strength as mentioned above by holding the Clutch with your finger. With the Clutch stopped, take a close look at the Gear. The Gear must not slow down whatsoever! If the Gear's speed remains the same when you stop the Clutch, then you know the Clutch is slipping properly. If it slows down the Clutch is too tight.
If the Clutch is too tight, then you need to shorten the length of the Spring. The lower picture shows how to do this with a pair of Needle Nose Pliers. Just grab the Spring right near the bottom, and bend it down. Keep doing this until the Spring is reduced to the desired length. You will need to re-install and test the Clutch a few times with differing lengths of the Spring in order to determine when the Spring is the proper length, and the Clutch slips properly. You remove the Washer and Spring by pushing down on the Washer, and pulling the Locking Ring out with Pliers. You do the reverse for re-installing it.
Use Pliers to bend the Spring down
Sankyo Clutch
The Sankyo Clutch is a contained assembly consisting of the Clutch and a hollow Shaft which is connected to the White Disc at the back. It fits over a fixed Shaft on the Camera, and is held in place with a Locking Washer. The Black Gear in the center is turned by a Drive Gear on the Camera. There is a Cross "+" Spring which applies pressure between
the Gear and the Disc, and this is supposed to slip when the Clutch stops turning from insufficient slack Film. The Clutch on this Camera was also way way too tight! To loosen it I simply bent down the four arms of the Cross "+" Spring with a small Screw Driver. I made the mistake of adding lubricating oil inside the assembly -- do not repeat this mistake as I couldn't clean the oil out! This oil made the Clutch too loose. You can see in the back picture a short piece of Tooth Pick which I inserted inside to stiffen it up. This Clutch now works perfectly which I can determine both by the Gear speed remaining the same when I stop the Clutch and by the Indicator Light in the Camera's Viewfinder. Down below is a picture of the base on the Camera for the Clutch which shows a Cotter Pin Switch on the bottom edge. The four knobs on the White Disc close and open the Switch which turns the Cartridge Indicator Light on and off. So, when the Clutch and Disc stop turning when the Film runs out in the Cartridge, the Light stops flashing.
You must also verify that the Clutch is not tugging on the Film by looking at the end of the Film in a used Cartridge. The end of the Film should not advance after the last Sprocket Hole has been pushed down by the Sprocket Arm. There should be about 5 Sprocket Holes of Film left in the Cartridge's Film Gate after the last Hole has advanced. If the Film at the end has advanced past the last Sprocket Hole, then this means that the Clutch is pulling the Film down, and it's too tight!
Cotter Pin Switch for Indicator Light
I can verify that as long as the Clutch in these Super8 Cameras is not too tight, these Cameras should never wear out. The only component on the Camera that could potentially wear out is the Brushes on the Electric Motor, but you'll never use it enough to wear out the Brushes. So little force is required to advance the Film through the Cartridge that there is nothing to cause these Cameras to wear out except a tight Clutch which will put a strain on all the Gears. This is why the plastic Gears in some Cameras wear out. Even with a cheap Camera, if the Clutch slips properly you shouldn't suffer jitteriness. It's very unfortunate that the Camera Manufacturers weren't more attentive to calibrating the Camera's Clutch properly. Jitteriness is probably a significant reason why many Super8 users quit using this format. You will also find the Camera's timing to be very consistent with a properly slipping Clutch. With this problem solved I hope that many former users will come back.
N. B. I have 11 Pictures to go along with this Thread. I don't know why they're not getting inserted. You can view my concurrent Thread on Cinematography.com to see the Pictures.
