Lauver, you still around?
I have a question for you. (Well a few actually)
1. Was the U circle stamp used exclusively during the WWII time frame?
2. We any of the WWII era sockets stamped in a manner that separated them from standard tools?
3. We any of the MILITARY use tools different from standard Craftsman tools? (Stampings, coating, distinguishing markings?)
4. Is there a list somewhere with all available sizes for the BE, circle H and the circle U sockets?
FWIW, I found a very nice example of an early =Craftsman= V open end wrench. One thing interesting is the "N" in the area between the 9/16 face and the raised panel. Any idea what that means?
T56,
Those are hard questions to answer because our entire knowledge of U-circle is based on only four tools (two ratchets, one sliding t-handle, and one socket; that's not much to go on.
That said, it looks like U-circle is rare, which would explaine why we have so few tools, and also suggests that U-circle may have been short lived.
So what do we know?
The dates for U-circle ratchets was 1944 - 1948 (the t-handle and socket have not been dated, but are thought to coincide with the ratchets).
Alloy Artifacts indicates that MDF began producing tools for Sears in 1938, but there is no tool or catalog evidence until 1947 when the V series tools first appeared. So, it would appear that U-circle dissapeared one year after V appeared. Sorta makes sense -- MDF becomes the principal OEM and Plomb (a short term OEM) fades into history.
If you read the old Sears catalogs from the war years, there is a lot of hoopla about Sears supplying tools to the war effort, both at home and abroad. I'm guessing Sears supplied standard tools. To date, there is zero evidence to support any special markings on Craftsman war era tools. On the other hand, there is evidence that war era Craftsman tools had less elaborate plating on these tools...look no further than the U-circle ratchet.
Regarding socket size lists for BE, H-circle, and U-circle series -- I am unaware of any such lists. But, with lots of careful work and a bunch of war era catalogs, you could probably build a representative list.
Regarding the forged "N" on your V series wrench, I have seen this and many other forge marks on Craftsman tools and non-Craftsman tools sold by Sears. Nobody seems to know what these forge marks mean; it could be that this is some kind of OEM artifact which has no significance to Sears or Craftsman tools.
EDIT: Regarding the finishes -- of the four known U-circle tools, the finishes are a mixed bag:
Ratchets(2)--Dull, unpolished, looks like tin/cad plating (examples are well preserved).
Sliding T-Handle(1)--Chrome/cad plated, not sure if polished (most of plating missing in example).
Socket(1)--Looks to be chrome plated, but not highly polished (example is in fair condition, owner indicated that the finish is better than the photo shows).