Pan American 58A Short Model
Date: 1949. Instrument found on e-bay, Owner unknown
The "Pan American" line of band instruments are Conn's "B" line, and were made by Conn in Elkhart, Indiana. Frequently they were produced for a specific vendor such as Sears. The serial numbers on Pan American instruments do not match Conn's normal serial numbers, so don't look it up in the Conn serial number list. Based on my current interpretation of the Pan American serial number list, this instrument was made in 1949. The fact that it is silver plated is somewhat unusual, far and away most of these were lacquered. This instrument has bottom spring valves. The bore size is a #2½, which is 0.484".
The 58A was preceded by the model 56A, which is essentially identical except for a main tuning slide rod which the 56A has and the 48A doesn't have.
This model is essentially the predecessor of the Conn 14A and later 15A Director models. When Conn decided to stop producing instruments under the Pan American name in 1954 and sell these under the Conn name, this model became the 14A.
As far as I can tell at this point, all Conn cornets built before 1958 take a short shank cornet mouthpiece as opposed to the 2¾" "Bach-style" long shank cornet mouthpiece. The long shank cornet mouthpieces won't properly fit a pre-1958 Conn cornet and won't give the proper intonation or playing characteristics of a short shank cornet mouthpiece. All of Conn's "Connstellation" cornet mouthpieces are long shank mouthpieces. The "Improved Precision" Conn mouthpieces such as the Conn 4 are long shank if there is a "ridge" halfway down the shank, and short shank if there is no ridge (in which case it is a "Precision" mouthpiece). All Conn cornet mouthpieces built before the "Improved Precision" series (ridge), such as the "Precision" series (no ridge) are short shank mouthpieces.