Eames Shell Cincinatti manufacture date  

its all full of....
Its all full of overlaps, contradictions and generalizations (and I know its all been gone over countless times before, but maybe I will learn something if do a run through...)
C = Milicron Cincinnati c. 1960s - unsure for how long
Circle "S" w "Herman Miller" embossed = later Summit c. 1960s to at least mid 1970s (many of these also have paper label and HM medallion)
2 triangles ONLY = earlier Summit 1955 ish to 1959 ish, (and usually has no other markings, or just the H with no "herman miller")
3 embossed dots and no other markings = 3rd gen Zenith, possibly 1954-1956ish ... dots are found dead center between 4 shock mounts
No markings whatsoever = 2nd generation Zenith (Venice CA studio) 52-54ish (but some of these had or may still have red Venice clear labels)
No markings on Rope edge chairs, usually just the checkerboard Zenith label.
Foot glides and bases are another indicator. But it gets choppy, as bases can be switched, so look for original mount impressions on the shock mounts. And it depends on the chair type.
Dates are not hard, so these are only generalizations, and there is a lot of overlapping and transitional combinations to be found.
Arm shell foot glides and bases go something like this...
Domes of silence glides: 1949-50 Rope edged Zenith shells on X bases (start date unclear)
Boot glides unsure of start date, but go up to 1954 at least, but possibly 1955 or 1956 still used
Earliest solid H bases start as early as 55 or 56, but mostly 57 ish.
Metal swivel glides introduced in 1955-56, even 54 possibly, but also sometimes found on 1957 chairs
White plastic glides intro'd in 1957 onward
And then there are the paper labels and medallions.
smaller earlier "patent number" paper labels as early as 1954-56 ish (unclear)
larger later white "patent number" paper labels 1955 onward thru 1980s
Herman Miller round metal white Medallion: at least as early as 1959 on armshells, and through the 70s, (associated with contract only and large orders for public spaces ? )
Whew.
(I have made my own list of this stuff, and it is always getting tweaked with each new sighting or piece of contradictory information....) I'm all for starting a "once and for all" list too.
PS: You know what I HATE? Misinformation. But its not easy, so excuse me if any of this sounds like total crap!
(Like that whole "dime in the mold" nonsense. I've seen the "dime" imprint on Venice chairs as well as Zenith chairs, so its not proof of "first run" of anything, as so many were touting on ebay awhile back. Its simply an early fabrication mark, and may at some point be narrowed down to a specific location or press. It is clearly a subtle fabrication mark, not a "dime" imprint. If it was just someone sticking a dime into the mold to release air, it wouldn't be so consistent every time.
Hope this helps.

That's fantastic EamesHead....
That's fantastic EamesHead. Very useful info. One piece of information that I have always searched for is the date that Cincinatti ending production of the chairs. At least with Zenith, Vitra etc we know between what years a chair may have been produced, then there are the labels, shockmounts and other subtleties that can narrow the production date even further.

Yeah hard to find anything on Milicron end date...
Is there a reason you are you aiming for a Milicron chair in particular?
For instance, maybe you live near the old plant and its a home town nostalgia kind of thing?
Or do you have some other shells or bases that are "correct" with that time frame?
One other thing I might mention about Milicron armshells is that sometimes (not always) there is a "waffle" pattern on the outside (reverse) of the shell that I have never seen on any other shells. (Perhaps this only appears on the early or late Milicron shells, and at some point we may be able to use it to refine dates further)
I will keep looking for an end date clue. Seems like they possibly went right up through the late 80s, but that is just a guess.

Waffle pattern
Seems to be only on certain colors, and only on the arm shells.

Thanks again. Not looking...
Thanks again. Not looking for a Cincinatti one at all. I just see chairs coming onto the market and I want to gauge the price and part of that would be the dating. To have best, most accurate information information possible will help decide a price to pay for a particular chair. I have see a Cincinatti chair and the price is very similar to another few I have seen which have more information about the date of manufacture ie They have a label. The chair is in great condition but if they were still manufacturing up until the mid 80s I don't think the price is really good.
I have also noted 2 variations of the Cincinatti Milicron raised logo/stamp. They both have the 'C' but the stars are different. One has this star http://www.usscatastrophe.com/anchovy/ebaypics/4.19.09/IMG_9788 and the other has this http://3.bp.blogspot.com/-ATN53vzcGVU/UDQE_AWwd0I/AAAAAAAABuo/yLYWP77C_y...
I have some information regarding the glides form EamesDesigns.com stating that "in Herman Miller production, I can tell you that the glides of some of the shell chairs changed four times between 1950 and 1957."
So many variations! I am determined to get an accurate timeline 🙂

That's impressive, EamesHead.
You are such a knowledgeable member of this forum...and sometimes you make me laugh.
yep,
Aunt Mark

and lets not forget the stamps...
such as the round stamped "Summit Prime", "AX", the big "Z", etc, and date stamped chairs with the actual day of the year... (often on the paper label chairs from 57 onward)
AND numerous other embossed marks I didn't mention earlier, like the rare small backwards "Z" (or zig-zaggy "S") in the center of those three small dots sometimes... and the embossed "cartoon flame"...
But much of this stuff makes little or no difference in value... at least YET.
Color can make a huge difference in price, and of course condition.
I guess large mount chairs (Zenith rope and "Venice" no rope) are one major line to draw in the sand, value wise.
Also, the "three dot" shells sometimes have the look and feel of Venice shells, and are most often found with small mounts, but I have found a three dot shell with large mounts as well. Bases get interesting around the three dot time as well.
Hey MARK thanks! (Just a little too OCD on the fun stuff I guess.) I know I have sunk more than my share of threads with my bad haikus, so I have to actually contribute something to the forum once in awhile, right?
And WOODY, yes, I have seen only Elephant Hide Grey and Red shells with the dryish looking waffle pattern on the reverse. Sometimes very pronounced, but often not that noticeable. Have you seen other colors? Blue or black comes to mind... but cant remember ...

..... ....... .....
sank a thread?..no chance
that you're a thread sinker...no.
evil in the womb.
Best,
Aunt Mark, serial fool

EamesHead
I have seen it on red, blue, black, Ochre Dark. I wonder if it was a more prevalent issue during certain production year(s).

woody
That seems a reasonable assumption, as quality-control measures would probably kick in at some point. Could be just one molding machine for one year... or maybe the mixture of ingredients?
I will never NOT notice time frames or dates on the waffle shells ever again!

Okay. So I contacted Herman...
Okay. So I contacted Herman Miller who basically told me I should go to an antique dealer and they don't have any records. Sent me a list of what previous employees remember but to be honest after trawling images of shell chairs with date stamps alot of that didn't bear true. The latest manufacture of Cincinatti shell that I have seen is dated 1977 but I am sure they go up to at least 1984.

Who
cares

I
do.
It's fun.
And there are at least two people here who would like to know.
We sometimes don't know what bits of information might become valuable or link up with other bits of information to provide context later on.

Very true EamesHead. After...
Very true EamesHead. After contacting EamesDesigns.com requesting information on dating a shell/chair they stated that they would actually like images and factual information regarding the manufacturing dates of chairs for their encyclopaedia.
I am going to build a web form for collecting such information. Maybe you could be of help, as I need to define, from the outset the information needs to collected.
The form will have image upload functionality and to keep things consistent I will provide image examples to people can take photos of their chairs from the same angles to keep the final information consistent and keep quality high. The images I was thinking are:
1. Of the chair as a whole
2. Of the underside of the chair to capture the markings/dates.
3. Of the shock mounts
4. Of the base
5. Of the feet ie H frame glides etc
Any others you think would need added to help ?
I also though a text field to add extra information such as when, where it was purchase, any history/provinence.
Also a field to enter contact details should something else be required.
What do you think?
Thanks,
C