Friday, February 16, 2024

Adjusting the paper feed mechanism - part 5

GOT IT! FEED ROLLERS AND THE PLATEN NOW MATE PROPERLY

I ended up loosening everything on the machine and disassembling quite a bit, before manually moving all the parts around until I could get the front rollers to come up and touch the platen. After that, I put parts back on and made adjustments, checking each time to be certain that paper feed the rollers worked properly 

READJUSTING THE PLATEN POSITION AND FEED ROLLERS

I set the platen using the Hooverometer to determine its height above the escapement rack and then to set the distance from the print shaft to the platen for the front-back positioning. I might have to tweak the height later when I am printing characters. If the platen is too high or low, the the bottom or top of a character will be faint. 

The feed rollers were adjusted to the specification, which is that with two punch cards inserted between the front rollers and platen, the rear roller should have a tiny gap to the platen. After going through all the settings, I am very pleased with the operation of the paper feed mechanism.

WORKING ON PAPER RELEASE MECHANISM BUT NOT DONE YET

Another lever on the typewriter allows the operator to release the feed roller pressure in order to feed in new paper or to move paper around easily. That lever has an eccentric cam which twists the release rod. On the rod are a number of adjustable tabs which can press on the spring loaded roller levers to move them away from the platen. 

The goal is to have a small gap with the rear roller when the release lever is operated, but achieve regular pressure on the rollers when the lever is not turned. The setting procedure sounds simple but in practice it is frustratingly difficult.

This is because the tabs on the release rod are fastened with a bristol opening bolt and nut. The nut is not held in place thus you need one hand to turn the bolt and a second to hold a wrench on the nut. But wait - there's more. The levers must be moved forward enough to achieve the gap - one hand to move the lever and another hand to test the gap with a feeler gage. 

Then, when the lever is at the correct position, the tab has to be moved up flush against the lever - another hand. The release rod can move away from the surface of the eccentric cam on the lever, so you must hold the rod pressing on the cam - yet another hand needed. 

If you are following along, that is six hands needed to adjust one of the four tabs. Fortunately the tabs do not have to be adjusted simultaneously - a serial adjustment  process works fine. Next time I am in the shop I will do battle again until I get the paper release set up properly.

2 comments:

  1. Sounds like a real trial and error process. I wonder if there is some way to reasonably accurately mark (or perhaps measure and record) where a tab is each time before you loosen it up to try a new position? At least that way you would know that you were trying a different position each time.

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  2. The real challenge is twisting the spring loaded lever one way, the release rod the other way, the tab against the moved lever, holding a nut and turning a bristol wrench. It isn't a matter of not knowing where the tab should be, that is pretty clear, it is a failure of execution traced to the lack of six hands.

    Not only would I need six hands, but they would have to be very tiny yet strong in order to fit in the same area while allowing me to see what was happening.

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