[GreenKeys] Progress repairing broken ASR-33 reader

[Jones, Douglas W]

See this photo:
-- http://www.cs.uiowa.edu/~jones/pdp8/UI-8/2013/12/16-TTYreaderRepair.JPG

The ears holding the paper-tape reader frame casting to
the main frame casting of the ASR-33 were broken, probably
by someone trying to use the paper-tape reader as a handle
to move the Teletype.  I made new ears from 1/8 inch by 1/2
inch steel bar, hot forged to a right angle.  In the
horizontal plane, the two ears were tilted forward at about
5 degrees, so I bent the new ears to lean forward by about
the same amount.

(Of course, before putting in these ears, I verified that
there was space for a 1/8 inch thick bar between the reader
body and the frame casting where these bars now sit.)

The mounting screws that hold the new ears to the old frame
casting of the reader screw into 6-32 tapped holes in the
steel bars.  I used flat-head screws, cut to length and
countersunk into the frame casting so they don't interfere
with the fit of the reader frame to the main frame casting.

Of course, things don't always go perfectly in these kinds
of projects.  I broke a tap in one of the holes.  It took
me some thought to realize -- hey, the tap is tool steel!
All you have to do is heat it to red heat and let it cool
slowly, and it will be soft enough to drill out.  So, I
heated the steel bar to red heat a second time, then (after
a break for dinner), I drilled out the tap, picked the
fragments out of the partially threaded hole with a scriber,
and then used a new tap to finish threading the hole.
Success.

		Doug Jones
		jones at cs.uiowa.edu