U.S. Army Signal Corps J-38
The quintessential military key is the WWII-era J-38, made for the U.S. Army's Signal Corps. For a thorough look at the J-38, check K6IX's J-38 site. The section on identifying the manufacturer of a particular key is particularly good. I have tried to follow K6IX's lead in assigning types to the keys.
(Click on the pictures to see additional images.)
Lionel Variation 1
The first issue of these keys came engraved with THE LIONEL CORPORATION in the base above J-38. The Signal Corps didn't appreciate the unauthorized engraving, hence the second variation.
Lionel Variation 2
This iteration, apparently the rarest, came with only J-38 engraved in the base. There is no Lionel logo on the bottom.
Lionel Variation 3
Maybe they forgot to put it on variation 2, or somebody just got a bright idea about the Lionel logo, but one of the casting marks on the bottom has been replaced with a stylized L. This seems to be the most common version.
The center of the frames of
all three variations is embossed with:
the stylized L inside a circle
THE LIONEL CORPORATION
NEW YORK, NY
The Winslow Company
According to K6IX, the Winslow J-38 is quite rare. Note the widening of the lever at the hammer (upper contact) and the captive wiring post nuts. Also, there's a circular logo near the back, left post, but it's very faint.
See the K6IX link above for information on this style of J-38.
All White Metal Style
Again, see K6IX for more info.
Reeve Electrical Co.
Made in Brooklyn, NY, the lever is stamped REEVE and is widened where the spring tension screw goes through it. In addition, the base is engraved KEY, TYPE J-38 instead of just J-38. (This key arrived in this condition & may be a victim of over-polishing.)