KBK update for Monday, 9th December

Theodor from Honeywell has delivered another batch of charts. Most are for 7A1H and 7A1M switches from Micro Switch KB but a few are for Micro Switch SD Series, including a replacement 2 M chart. From the latter, we now learn:

• Keystems S and T denote switches with a small ridge around the plunger aperture (the 0.05″ extra bearing surface mistakenly conflated with the 0.05″ taller plungers in the black-plunger types). The plunger is drawn the same as for 4 A and 4 B, but each plunger type has a different part number than for the standard switches, so they may still be different.
• The flat-stepped plunger style is “N” not “H”. This is clearly readable on the new high-quality copy of chart 2 M, but on the fax-resolution copy from Al Kossow, I misread it as “H”.
• The are three custom plungers for NCR: C, D and H. Chart 4 A does not say which is which: C is listed first but depicted in the centre. All three are quite different. Just as how Datanetics made a custom DC-50 type for NCR, it seems that Micro Switch made various custom SD types for them also.

The 1001SD charts PDF is re-uploaded (now with “M” in the filename) with a replacement chart 1 and the A charts deleted; this PDF is now M charts only. The available A charts are placed into a separate PDF.

Details of 7A1H and 7A1M will be posted once I have had time to digest the charts, some of which have suffered in quality during archival at Honeywell. One curiosity is that the split between “quick connect” H and solder-terminal M is not perfect, with one H type seemingly having solder terminals. Also, KB reed switches supported quad pole.

View within the updates for 2019

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