Key as relay

In the olden days of the 20th century Morse code keys were so common and cheap that you could do stuff like this:

source on page 38: 

https://www.worldradiohistory.com/Archive-Radio-TV-Experimenter/Radio-TV-Experimenter-1967-08-09.pdf

BTW, I don't know what they are talking about at the end: "since most keys have both a make and a break contact" - I've never seen this - keys are single-pole-single-throw AFAIN.  I think the only way I could sanction this project is using one of those cheap keys with a plastic base like this one that came with the Knight-kit LC-1 CPO:

Now Digi-Key doesn't sell keys (if they ever did).  They *might* sell you Fahnestock clips:

(the key relay uses two Fahnestock clips) at $3.54 each in quantity 1000 and they have to be special ordered !

Yeah, I don't think I'm going to go into the key as relay kit business anytime soon !

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm