I have looked around a bit and it looks like both were available at same time during ww2.
Thanks, OTG, that lends further credence to my position.
The War demanded urgency.
Did you miss the fact the M-10's with the detent ball were being made throughout the war?
"The War" was not a monolith. Anything but, despite the efforts of the WPB. One of the reasons the Military-Industrial Complex grew so much more centralized after the war (DOD, DLA, GSA, etc) was how inefficient and ineffective acquisitions and logistics were with multiple technical services, bureaus, and contracting agencies within services. We managed to win the war
despite that slogging quagmire, which is the theme of every major military institute's book on WWII.
I guess I can understand the fixation on why it was not provisioned in the 1/4 drive size, but that's only half the question. The equally if not more interesting and important half of the same question is,
Why was it provisioned in the 9/32 drive size? And if you haven't been following my little survey in the Midget thread or my mini-reports back here where the question originated, it doesn't look like the answer is because 'they just always did it that way.' It doesn't look like the detent ball is a case of something industry was regularly doing, and then it was dropped to make the midget socket wrench portion of the war machine more efficient. Prewar Snap-on M-10's did not come provisioned with a detent ball. While Plomb never sold 9/32-drive tools commercially, their 1/4-drive hinge handles never had a detent ball. The hinge handle they made for the USAAF
did, though. I think this is all looking like very strong derived evidence that the detent ball is something Snap-on and Plomb added explicitly because of the USAAF, the primary (and perhaps exclusive) customer for 9/32-drive midget tools. I just don't have the kinds of documents for the USAAF that I have for the Ordnance Dept and others to definitively prove it.
Expedience and cost-savings may have been the reason that the Ordnance Dept didn't specify detent balls in their 1/4-drive midget hinge handles (or, as I already suggested upthread, the hinge handles in standard commercial midget sets they used as a model were already being made
without detent balls), but I am convinced that the USAAF considered that secondary in priority to keeping those tiny danged 9/32-drive hinge handle crossbars from becoming F.O.D. in and around their aircraft.