I've had a lot going on lately, and other than my beautiful 1941 T.R. McElroy P-500 Mac Key, I've not written a about code keys.
I have been saving a USPS Priority Mail box that arrived a couple of weeks ago. It's been under a table here in the shack, and I wanted to wait until I had a little time to enjoy opening.
Tonight was the night.
Actually, the box had that ominous “clunk” when you moved it, and as naggy as I am about giving sellers instructions for shipping bugs, you can imagine my fear of damage to yet another not-quite-rare-but-mint-condition T.R. McElroy key.
Thankfully, my fears were unfounded.
The key arrived intact, complete and undamaged: The key is a 1939 T.R. McElroy Mac Key Standard.
The 1939 key was the last of the Mac Keys that still was an obvious “Mac” key — it was the last to have the same type of “T-Bar” pivot frame that had been a characteristic of McElroy's bugs since they were introduced in 1934. The key had the large metal ID plate with serial number that McElroy bugs began using in 1938 (it was a modified civilian version of the military ID plate used first by Mac in 1936).
The biggest identifying characteristic on the 1939 model are the uprights on the “T-Bar” — the uprights are much wider than they were on earlier keys. Wider, not thicker; in fact, they were nearly twice as thick as the earlier ones.
I don't know why the design changed, and I've not read any explanation for the change. The 1939 model — both the Standard one like I have and the DeLuxe “marbelite” finish versions — are not real common. The 1939 key represents the end of the line of development McElroy had for his own line of keys. The following year his keys began to look more and more like knock-off of the Vibroplex bug.