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J-38 Key
Nomenclature & Parts List

(also see the picture at the bottom of the page)

The end of the key nearest the operator when the key is being used
The end of the key furthest from the operator when the key is being used
The side of the key to the operators left when operating the key
The side of the key to the operators right when operating the key
The thin, flat, rectangular (3" x 4 3/4") Bakelite slab to which the Frame is attached
The heavy, oval shaped metal support for the main parts of the key, including the Lever and Trunnion
Lever and Trunnion:
The flat, cross-shaped steel piece which is moved up and down using the Operating Knob
The longer piece of the Lever and Trunnion
The shorter cross piece on the Lever and Trunnion
Operating Knob:
The Knob or Button used to operate the key to send code
The upper electrical contact, attached to the bottom of the Lever
The lower electrical contact, attached to the top of the Frame
Anvil Strap:
"L" shaped thin metal strap connecting the Left Inner Binding post to the Anvil. (The Left Inner Binding Post, the Anvil Strap, and the Anvil are insulated from the rest of the key)
Circuit Closing Switch:
The thin, movable, "S" shaped metal strap attached to the rear of the frame and extending forward to the right of the Anvil Strap
Circuit Closing Switch Knob:
The small knob next to the Operating Knob used to move the Circuit Closing Switch
A series of small ridges along the edges of various screws and nuts used to connect and adjust the key. The patterns of these ridges sometimes provide evidence for identifying the type or manufacturer of a key.
Thumb Screw:
A screw with a knurled head, allowing it to be tightened/loosened by hand. There are 8 Thumb Screws: 4 are Adjusting Screws and 4 are Binding Post Screws.
Adjusting Screw:
A Thumb Screw used to change the position or operation of parts of the key
Gap Adjusting Screw:
The Adjusting Screw threaded into the Rear of the Lever
Tension Adjusting Screw:
The Adjusting Screw threaded into the Lever near the Main Knob, which is used to adjust the Spring tension
Trunnion Screws:
Two Adjusting Screws, one threaded into the support on each side of the frame, which hold, and provide a pivot for, the Trunnion
Lock Nuts:
Knurled nut on an each Adjusting Screw shaft, between the head of the screw and the piece into which the screw is threaded. There is a Lock Nut on the Gap Adjusting Screw, Tension Screw, and each of the two Trunnion Screws
Binding Post:
A device used to hold, and make contact with, an electric wire. There are 4 Binding Posts: 2 Inner Binding Posts and 2 Rear Binding Posts
Binding Post Screw:
A Thumb Screw threaded into the top of a Binding Post
Inner Binding Posts:
The two Binding Posts on the Rear of the Frame
Rear Binding Posts:
The two Binding Posts nearest the Rear edge of the Base
Binding Post Positioning Pins:
Wire pins inserted into the bottom of a Binding Post to prevent it from turning. All J-38's have positioning pins in the Rear Binding Posts. Lionel J-38's also have positioning pins in the Inner Binding Posts.
Rear Shorting Strap:
Thin metal strap connecting the Rear Binding Posts to each other
Coil spring between the Frame and the Tension Screw
Spring Holder:
An indentation in the frame or a small metal lip attached to the frame to hold the bottom of the spring

Two Lionel J-38 keys

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