[GreenKeys] Teletype 33 punch adjustments

[Jones, Douglas W]

We're trying to adjust the paper-tape punch on our Model 33 here at the U of Iowa, and we're following the manual farily carefully, and have run into a bit of a brick wall.

The transmitter distributer works, and when we type the numbers or letters in alphabetical order, we can see the code bars counting in binary order.  This is very encouraging, but the punch?  Things go wrong.

The basic problem seems to be that when we follow the adjustment procedure, we reach the step where we're supposed to check the depth of the punching stroke, none of the pawls catch, so of course, the stroke length is zero.  We're using a feeler gauge to judge the stripper-bail adjustment -- it says to do it by eyeball, but black metal working against black metal is very hard to adjust by eye in deep shadow, even with a bright flashlight to help.  Suggestions from those who have experience with adjusting Model 33 punches?

(The normal advice, of course, is not to touch the adjustments, just oil and clean being careful not to change anything.  This doesn't work if other problems (extreme dirt, broken parts) force you to disassemble your machine to the point where re-adjustment is needed.)

               Doug Jones
               jones at cs.uiowa.edu