Winchester (founded 1855) started marketing tools about 1919 to fill up post war (WW I – July 28, 1914 – November 11, 1918) production capacity. Some tools they made, but to fill out the line they subcontracted some as well. The regular bench plane line was made by Sargent, and Stanley rebranded Winchester planes that were from their Bedrock line.
During the 1920’s, Stanley manufactured Type 4 Bed Rock Planes for Winchester. The planes were identical to the original Stanley’s, except for the markings on the beds. These were Winchester trademarks on the blades and frogs with twisted lateral levers. Winchester Bed Rocks had Winchester marked lever caps. (Ref http://www.antique-used-tools.com/brtypes.htm)
I haven’t confirmed when they stopped, but I’ve read it was until WWII.
This is my Winchester 3005 (Stanley #4 size or Sargent #409 size)
This one is probably circa 1919
This is my Winchester 3004 (Stanley #3 size or Sargent #408 size)
This one is a few years later.
This is my Winchester 3020 (Stanley #7 size or Sargent #422 size)
This one is probably circa 1919