[GreenKeys] [External] Just bought an Ebay ASR33 in the UK

[Jones, Douglas W]

From: Rob Jarratt <robert.jarratt at ntlworld.com> -- Sunday, February 9, 2025 12:58 PM

> Stand screws: 6-40? What length please?

No.  I'll quote myself from:
-- https://homepage.cs.uiowa.edu/~jones/pdp8/UI-8/log2015a.shtml#2015-01-13
As noted on Feb. 11, 2014 there were only 3 bolts out of the 4 required to properly mount the Teletype sub-base. Inspecting these bolts, no two of them were the same, and none were exact matches for the two options mentioned in the Teletype parts list. The parts list indicated that 10-32 screws and had been used with an early version of the sub-base casting, while later production used a self-tappng screw and spring clips.

Note that 10-32 screws and M5 screws are so similar that they are frequently interchangable -- 10-32 screws fit most M5 nuts and visa versa.

If your TTY has a stamped low-carbon steel base pan, it probably used self-tapping screws and spring clips.  If it had a diecast zinc base pan, all bets are off.  I had a cast zinc base pan, and I ended up making custom-made 10-32 nuts that fit square recesses in the top of the base pan.

These screws, in all cases, are designed to be screwed in from below.

It's fairly easy to remove the top from the base while the machine is assembled, but putting the top back on is tricky unless you strip it down to a bare base pan.  You may want to do this anyway in order to replace the foam pad that sits on the base pan under the mechanism.  Your old pad is probably  turning to mush, and new pads can be made from new foam.

            Doug Jones