[GreenKeys] Model 26

[George B. Hutchison]

Howdy All - - -

A word of warning to the Model 26 folks...

One of the weakest designs in all of teletype was the stop arm on the 
type wheel shaft of the model 26.

It is cast aluminum, as I recall, and they were a pain to replace.

The bad part of the design is that there is a felt clutch driven 
directly by the motor that is the source of power for turning the 
type wheel.

If the clutch is not adjusted tight enough, then there is a bit of a 
time lag when the stop pin where the wheel would be currently 
positioned, and the next character was selected, at which time the 
stop pin at the current position would withdraw allowing the stop arm 
shaft/typewheel to begin to rotate to the new position as determined 
by the new character decoded by the selector.

The stop arm would then engage and latch in the new position, and the 
printing cycle would complete by the print hammer whapping the back 
of the pallet.

The "RY" character combination is such that the type wheel must make 
almost a full rotation when going from R to Y, but when "YR" occurred 
the type wheel would have to make a full rotation  plus one character 
going from Y to R. A model 26 which successfully produces several 
lines of RYs is in good shape.

A common practive was that to get the RYRYRY combo to work 
successfully, adjusting the tension on the clutch at the bottom of 
the typewheel shaft would get it right. This is true. However, 
sometimes someone would adjust the clutch to be way too tight, which 
would result in overheating of the felt clutch, and increasing the 
possibility of  causing the latch on the stop arm to break off, 
resulting in a typewheel which would spin endlessly, putting the 
machine out of commission.

So, beware, as that excessive clutch tension could cause you some 
heartbreak if the stop arm broke. Model 26 parts stores are few and 
far between, and the stop arms are almost always out of stock.

The keyboard feel and sensitivity was excellent. It was almost as 
good as a model 15 with hard-faced keytops.

Congrats on your machine.

George - W7TTY