[GreenKeys] Model 28 Re-gearing for 60 WPM

[ad7i]

Greetings --

I have a 28 RO that's currently geared for 75 WPM.  It runs great and I'm
very happy with it.   I'm using that 75 WPM RO machine as my test vehicle
to try out some ideas I have for low voltage electronic selector magnet
drivers.  I want to do that work on a 75 WPM machine because the timing of
the selector magnets would seem to be more "fussy" at 75 WPM than 60 WPM.

To solve the problem of running a 75 WPM machine on things like 60 WPM
ITTY, I have an Arduino that implements interrupt driven bit-bang UARTS,
the receive UART running at 60 WPM and transmit UART running at 75 WPM.
The received data from the RX UART then goes to the TX UART.  Five bit data
in, five bit data out.  It works, but of course the operation of the 75 WPM
TTY driven from a 60 WPM source is far less than smooth and rhythmic.
Instead, it's a bit of irregular staccato sound.  It sounds like the
machine is frazzled.  I want to try some buffering of the incoming data
with outbound flow control, to make the 75 WPM TTY sound smoother when
driven from a 60 WPM source, but I'm pretty confident that when I've got
that working that I won't really like the sound of the resulting TTY
operation.

So............  Once I'm finished with the selector magnet driver project,
I'd like to re-gear the 28RO for 60 WPM operation.  But I don't have a clue
how to do that.  Its that a big project or small?  Are all the gear changes
done only to the gears on the base, near the motor?  Or do gears need to be
changed on the typing unit as well?  Are the correct gears for 60 WPM
operation commonly available?  Etc, etc.  I'd appreciate any advice
Greenkeyers may have to offer on the topic of re-gearing a model 28 RO to
60 WPM.

Paul Newland, ad7i
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