Quote from billycgribble on June 30, 2013, 12:15 am

Red rubber stamps are marking devices.

So these are engraving companys?

Some might be. But red rubber stamp companies make marking devices (and some made tokens and other die struck items like desk plates, name tags, etc.). Postal cancellation machines are marking devices. The Marking Device Association was a donor to a Smithsonian exhibit on postal covers in the 1980s for example.

Quote from billycgribble on June 30, 2013, 1:12 pm

Bob, Here are the two examples that you didn't post. Three questions for you and for all our other collector friends. 1. Since they included HK-751a as a uniface piece in gilt bronze it would seem reasonable to include the aluminum piece as well? 2. I share your reservations about this organization. We have HK-750 the 45th convention 1959. We have the 47th convention 1961 for HK-751d. We have the 50th anniversary in between (not regular convention) Since I'm sure everybody has thought about where is the 46th convention, do we include it because it is part of an established series even though it was held in Toronto? It is dated in progression as 1960. 3. Lastly, an ASSOCIATION is a group of individuals with like interests. Can you or anyone out there explain what these individuals did? I would like something besides "MAKE MARKING DEVICES" although explaining what these marking devices are would be partly ok. ,