Anyone with a vintage Knoll Saarinen tulip table  

aluminum is not magnetic...
aluminum is not magnetic (it's relative permeability is about 2.2), iron is (it's relative permeability is about 720). if a magnet sticks, then it is probably not aluminum.
as far as i know, the newer knoll bases are made of aluminum.
i can;t put the magnet test to work, but i would say initial impression is no, it is not aluminum and therefore not knoll. however i have not tried the magnet test and knoll may use some alloy compound that is magnetic.
sorry to be convoluted, but i would say not real
anyone else?

Hi
Send pictures of the bot...
Hi
Send pictures of the bottom weights, the table top connection, the table edges, the stem profile to ssguy66@yahoo.com and I will give an opinion. Knoll side tables from the early days were cast iron, but probably not the dining base. It should be a thick casting though, and if its not that, its not Knoll. Some were made of spun sheet metal, some missed the shape, some connect the top with 4 screws. These give clues.

I sent pics. The base is a...
I sent pics. The base is a single massive cast piece of metal. A magnet sticks tight. The wood top attaches by an intermediate wood disk screwed into the top. This assemblage then screws onto a single threaded rod on the top of the base. The disc has four short wood dowls sticking out the bottom that position/center the top over the rod. Then turn the top to screw it down.

I would say that Knoll cast...
I would say that Knoll cast these bases in iron at some point, Please weigh it and tell if its less than 100 pounds!
genie Knoll and I would bet 100 on this

75lbs on a bathroom scale.

I am nearly certain that...
I am nearly certain that I've read that older version of the Knoll Saarinen tables do not have an aluminum base.

I was recently corrected on another post...
And rightly so... I remembered that the Saarinen bases were cast iron... This was in my mind as a fact... In refering to the latest Knoll Studio spec book they show the bases as cast aluminum... Not sure when the change happened but I'm pretty sure, as per your description, the table you have is authentic and an original.. It's also nice to know I may not be "losing it"...

Just a thought...
I think it just as likely-if not more likely.... the base was never iron.Reason: there was a push to promote aluminum after the war esp among progressive designers.Weight is a big factor in moving furniture in the home and shipping.

I'll clear this up or die...
Will get in touch with Knoll directly and get the answer we are all dying to hear... I have to do this to validate my own sanity... Will hopefully know something soon...

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Good,I was thinking...now I must know!good luck...

iron it out...
Early versions of the Knoll table base were 100% definitely produced in cast-iron. They're obscenely heavy. I have one that is marked on the underside with the Knoll label and the connection between top and base is identical to your description so I'd be willing to bet that yours is authentic. IIRC the reason for using cast-iron had something to do with the technology to cast aluminum in that form not being fully worked out at the time, something about the cooling rate of the aluminum causing stress fissures etc.
Okay, just did a quick search, this should clear it up for good. http://purecontemporary.com/AsktheExpert/question/12

Cool
So my table is real and real old. Any ideas when the shift was made from cast iron to aluminum?

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Great link this woman is a docent at the KNOLL museum...great info!

Confirmed!
The Director of Knoll Studio in NYC just emailed me saying... "originally the bases were in cast iron... now they are cast aluminum"... He did not say when the switch took place... So I'm not crazy...yet...