Nice article, Hans.

The Vibroplex Presentation key is a wonderful key with its adjustable mainspring (loosen two screws and pull or push the mainspring in or out).

The earliest Vibroplex models had an adjustable bearing screw on the top of the trunnion arch, but operators who were not used to the synthetic ruby bearings inadvertently cracked the bearings, requiring repair and often sending the key back to Vibroplex in Brooklyn, NY.

Vibroplex instituted a design change by eliminating the top adjustment screw, but this left an unsightly hole on the top of the key, which Vibroplex improvised and had a "threaded red decorative piece" to screw into the hole at the top of the trunnion.

This unfortunately led to new operators thinking that this little decorative piece was the "jewel" but it isn't, the bearings at the top and bottom of the pivot pin are cups of man made ruby which provide nearly frictionless movement but unlike the standard metal bearings are prone to cracking if overtightened.

N1EA

On Fri, Jan 7, 2022, 23:51 Hans Brakob <kzerohb@gmail.com> wrote:

Twin City DX Association publishes a quarterly newsletter online, the “Grey Line”.

About 20 pages of the current edition deals with Morse keys and learning Morse.

Read it here, starting at page 11.

https://tcdxa.org/wp-content/docs/Newsletters/Dec2021GrayLine.pdf

73, de Hans, KØHB
“Just a Boy and his Radio”™

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