Apparently, I do a lot of stumbling in my life, and I coincidentally recently stumbled across what appears to be a few "new" U.S. test stamps.
But, there is kind of a weird background. So sit down and buckle in for a brief story.
The Clipless Paper Fastener Company of Newton, Iowa, made a rugged handheld device in the 1910s that attached paper together without using paper clips. They also made a larger "desktop" model that did the same thing.


They can be found on eBay without too much trouble

These two coil pairs, recently discovered, seem to show these two specific devices.


So why would Mr. Hawkins, the owner of the company, pay to have these coil stamps made?
Possibly to demonstrate the operation of his new stamp vending device, which he patented in the 1920s:

No trace of this device remains today.
The author believes that the coil pairs shown above were used as test stamps for Mr. Hawkins "stamp vending machine," which was apparently never actually produced.
What do you think?
Jim