After buying a Vitra rocker last year, I've bought myself a second rocker(No Vitra) a few days ago and I would like to know a bit more about the possible date of production and location.
It has a lot of symbols on the bottom:
- On the shock mounts is the letter "Z" or "N" visible.
- Double intersecting triangle
- The letter "S" with a circle around it
- The logo of Herman Miller with underneath the full name
- A stamp with I think "Summit Prime"
- Under the stamp is a 4 digit number visible "3 241"
- A sticker with information about patents (difficult to read), on the bottom left of the sticker is the number "863" stamped in red.
I've already looked around for a bit more information about the age of the chair but I haven't found one yet who has that much of information on the bottom.
The rocker feels like it has a roped edge(if I compare it with my Vitra rocker which hasn't got the rope edge) but the rope is not visible, but it feels rounded and thicker on the edge.
The fibers are a lot more visible than on my Vitra rocker and are also better felt.
I've asked the seller about the date but he could not tell me much about that, but what he did know is that the shock mounts are original but the base is newer.
I've read that more information on the bottom means less age of the rocker. But I'm not sure because of the S and the double triangle...
I've paid 750euro for it with a guessed production date from seller of about 1963 but he wasn't sure at all. I think I may have paid a bit to much for it but when you fall in love with something at first sight you don't look to much at the price:)
Thanks in advance,
Jens, BE 
circle S and "HERMAN MILLER" embossed...
This is a Summit Plastics, Kalamazoo MI shell made in the 1960s or later. Could be 60s or 70s... it is hard to fine-tune the time frame more than that without provenance.
This is not a rope edged chair.
But Elephant Hide Grey is one of the most desirable colors, and this is a very nice example!
Shock mounts on these are correct to the chair (smaller type), but not sure if these are replaced or not. Hard to tell from this picture if the base is a repro but if the seller says the base is "later", than it is probably a good reproduction rather than a vintage later base. (I could be wrong about that though!)
Silver number...
The silver round stamp is a "Summit Prime" stamp. Just another typical characteristic of the 60s Summit chairs. The silver number probably is just a lot number or production number of some kind, but not a big deal in itself.
(If the shell had no "circle S" and no HERMAN MILLER embossed letters but only triangles, it would be late 1950s) The circle S is the main characteristic that nails the timeframe as later Summit Plastics roughly 1960 or later. Paper labels can be found as early as 55, but run through the 80s.
Some others here might know if the silver stamp narrows down the date a little more, one way or the other, but I don't. My guess is 60s but just a guess.
The Vitra chair is very nice too!
PS Price is probably because dark grey is a very coveted color, and it appears that the chair is in excellent condition with no edge chips or cracks or scratches.
If the base is later but original, the price would be in the ballpark I think. Maybe a bit high if the base is a repro, but then I am not in Europe.
base of the rocker
The age of the shell is recognizable from symbols on the shell, but what about the base, how can you see the difference between an old and a new one? Of course wear is a big one but what else?
I found another rocker this afternoon with a silver sticker with the logo and name of HM on it and the inside of the shell was covered with leather. Don't know if the owner did that but felt like the chair was downgraded with the leather. But the base on that one looked older then other ones but couldn't see much of physical differences between the bases.
there are padded chairs...
... with authentic bases. Go to EamesDesigns website and look under "seating".
It's possible the seller could have paired your shell up with a later but original base. But you made it sound as though he hinted that the base was a repro.
You would have to post some close up pics of the base and runners and wait for some of the rocker base experts around here to weigh in.
It's all in the details. Things like the mounting tabs at the shock mount area, and how the metal is shaped where the metal hits the wooden runners, and the paint, and the thickness of rods, etc. Also the shape of the runners themselves, and the patina or lack thereof.
Does it "feel" old? If not, it probably isn't.
Base is 100% sure a...
Base is 100% sure a reproduction.
Price is normal retail in Europe for this color and armshell in very good / excellent condition.
Red stamp on patent label is the date, so August 1963.
Original a h-base was attached to shell, which can be seen by the imprints of the shock mounts. And yes they probaly are re-glued.
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