Done adjusting the paper feed mechanism, adjusted cycle clutch as well

READJUSTED THE PLATEN POSITION TO GET THE FEED ROLLERS CORRECT

I figured that I won't make any changes to escapement rack positioning at this time, simply get back to where I had feed rollers that pressed on the platen and released properly with the paper release lever. From there, I would deal with the carrier movement issues and then get back to the remaining adjustments and tests on the machine.

While I couldn't get the front rollers completely in place, the gap was only about the thickness of a punched card. I inserted some paper and realized that the paper feed holds the pages well and feeds properly as it is, so I am closing the book on this adjustment and moving forward. 

CYCLE CLUTCH FINAL ADJUSTMENT

The print cycle clutch is a fundamental mechanism that I wanted to get just right. It is a clutch type widely used in the typewriter where a coil spring rotates around a metal drum, with one end of the spring fastened to the motor pulley which is always turning and the other is either loose or held by the clutch actuator.

While the one end is loose, the spring coil returns to its natural shape, tight on the inner shaft, and thus will turn the shaft. When the end is held, however, the spring coil unwinds to a looser coil and the inner shaft slips around without disturbing the coil spring. Thus, holding the end of a spring stationary will keep the clutch from activating and turning. 

The outer cylindrical piece that fits over the coil spring, with the spring sandwiched between the inner shaft and the outer cylinder, will rotate with the loose spring unless it is held by a tab that projects to hit one of two steps in the outer surface of the cylinder 180 degree apart. The tab is the cycle clutch release arm, normally it is jammed against the tab on the outer cylinder keeping it from rotating. This opens up the coil spring so that the inner shaft is not forced to turn.  

When a print operation is to take place, the clutch release arm is pulled away momentarily, the coil spring tightens up and the entire assembly now turns including the inner shaft. A cam and roller on the outside forces the clutch release arm back so that it blocks the next tab, stopping the clutch after exactly one half turn. 

The adjustments for the cycle clutch involve three things. First, the end of the coil spring that is held or allowed to turn is moved around the circumference of the cylinder so that the coil loosening takes place just before the end of a cycle, with the momentum of the moving pieces producing the last few degrees of rotation.

The clutch must stop so that a check pawl drops into a slot on the end of the inner shaft. The two slots are the idle positions of the print mechanism. The clutch should come to a stop with the pawl just able to fall into the slot. For that purpose, the clutch cylinder has overthrow stops that let it bounce slightly past the stopping point from momentum, ensuring the pawl engages to hold everything in place.

I want the adjustment for the coil spring slipping at the end of a cycle to give me the solid check pawl engagement. At that point I adjust the overthrow stops that allow that small amount of excess rotation as the clutch stops. One Bristol head bolt for the slippage and two screw adjustments for the overthrow at the two stop positions 180 degrees apart. 

The adjustments were a bit tedious but eventually I had this dialed in perfectly. The benefit is that it corrects an error that existed up to now, where the ends of the tilt and rotate selection levers had not popped back under the bail at the end of a print cycle. They do now, everything looks good to move on and finish up the other adjustments.