[GreenKeys] Tape sprocket pitch?

[Duncan Brown]

Did the TTY tape sprocket pitch change between the 1930s and the 1940s? 
Or would you typically see some variation in pitch between two machines?

I made my Christmas Music tape on a AN/FGC-9 (M19) punch and then made a 
copy with a "Single Magnet" reperforator that sits on the little dolly 
under the M19.  The reperf had worked fine the last time I used it (a 
year or two ago) but this time it was missing (not punching) a few holes 
in the 4th & 5th rows. Luckily, I had my Pettey "Perfect Poultry Punch" 
with me, so I just put the original tape and the new tape together, 
looked for missing holes and then punched them.  But as I moved down the 
tape, I had trouble keeping them aligned. When I finished punching the 
missing holes, I held the two tapes together with the same starting 
points and found that one tape had four more characters than the other! 
Four characters difference in about three feet of tape.  Is that typical 
or was there a change in the pitch between the two different machines?  
The M19 is WWII vintage and the "Single Magnet" is probably not much older.

Any thoughts??

Duncan
K2OEQ




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