Early Coil Stamps

"As a matter of classification I think it ought to be obvious that stamps "issued" as coils are not in the same collecting category as coils privately produced from existing stamps.";

Absolutely. The pre-1908 "coiled stamps" that were privately produced should be considered, for practical purposes, as "Forerunners" or "Experimental" in nature. Although some of the 1850s products were commercially available. They obviously did not attract the attention of the Post Office Department enough (if at all....) for the POD to be interested.

For anyone seriously interested in learning more about the "fore-runner" material, or about the subject of private coils in general, there are articles which contain some information in the following;
1. "Guide to United States Vending and Affixing Machine Perforations, 1907-1927" by Belasco;
2. "The Stamp Machines and Coiled Stamps"; by George Howard;
3. Articles in The American Philatelist for March, 1994, September, 1994, April, 1995 and May, 1995 by Ken Lawrence.

Here you go. There is an example of an early "coil" affixed by the affixing machine on page 4. of this document.

http://www.rfrajola.com/mercury/farwell.pdf

I'm going to say one thing only on this topic "rouletted imperforate"

There's an early coil on ebay. Search "dr jim scott 35 Washington".

Hope this adds to the topic!

This is a great discussion! I didn't realize that coils dated back that far although I am aware of and seen completely imperforate Colombian issues! I thought them very interesting albeit prohibitively expensive but interesting none-the-less! Cheers!

There is an interesting article in the January 2018 issue of The American Stamp Dealer & Collector by Arthur H. Groten entitled "George K. Snow and the World's First Coil Stamp". Might shed some light on the use of an early patented affixing machine creating "Coils". Interesting read in any event.