Mechanization started to come in by the mid 1950s. Substitution of machine power for human muscles. There was still hand work in placing the cymbal and triggering the machine to put the stamp on. Same with hammering the cymbals (preliminary shaping by Quincy Drop Hammer).
Automation came in much later. I'm not sure if you would say automation for stamps until microprocessors were involved with the laser stamps starting in 1994.
The Zildjian reference to "rolling in" stamps comes from their advertising material for the 2016 A Avedis series.
"Rolled-in" A Zildjian Trademark
The pdf is available via my web site by clicking here. I'm not responsible for what terms they use and why. My responsibility ends at correctly reporting what they say and providing the references.
Yes Zildjian went back to using a pressed in die stamp in 2016. I bought an 18" A Avedis just to be able to have hands on and do microanalysis on the trademark stamp, check the bell size, lathing, taper, etc. It's the 1960s short stamp brought back into use.
I've got hundreds of examples of flaws in the way the trademarks appear because that was part of working out what different attributes can tell us about the stamps and the technology. You need to examine enough of them to learn about what represents one off variation in the way they were pressed in and what represents something which has systematic variation which might indicate chronology or something else.
Here's a "70s stamp" example which is lightly pressed in except for the top half of the AVEDIS. That makes me wonder if the AVEDIS is able to move about slightly in the holder, and in this case the top portion of AVEDIS was a bit higher than the rest. If this same pattern appears in a large number of "70s stamp" impressions then perhaps the tool and die maker who created it made the top of the AVEDIS slightly too high. So we need to know how commonly this fault appears.
[img]http://black.net.nz/avedis/images/20-2258-stamp.jpg[/img]
It turns out there are stamps (both 60s and 70s) which show the thickness of the AVEDIS characters varying. They are quite thick at the top and thinning towards the bottom. Another hint of tilt within the holder and/or the die made slightly off. Yet these flaws are only found in some but not all of the stamp impressions. Then there are microalignment differences in how close the AVEDIS is to the ZILDJIAN co versus the dot dot dash dash at the bottom of the Ottoman section. Research on these is ongoing but not a high priority for me. I've got lots of other research projects on the go.
These sorts of stamping flaws are separate from the occasional cymbal which gets two trademarks, like this example which shows two different stamp eras overlapping:
[img]http://black.net.nz/avedis/images/double5060.jpeg[/img]
One of these is a late 50s Small Stamp. The other is an example the LS2 (Large Stamp with 3 dots) which started this thread off.