Hello everyone, I am looking for help determining A) what I have B) the market for such an item C) clearly some sort of value:

I have a vintage Pneumatic William H Keller Inc. Screw Driver Model # 1086. I am in charge of an estate and came across this
interesting piece which has sparked my curiosity to the point where I find myself here, looking for any help possible.

From the research I've done this tool comes from as early as the 20's. But not certain. I've given the model #, as well as manufacture from
its Era. What ever the help I can garner, the better. Anything from opinions on how to continue my research to establishing a reputable broker/estimator etc.

I will upload a photo as soon as I can.

Air driven screwdriver?  Never seen one.  I Need pics.

Not this one?- http://www.prior-ip.com/patent/3339823/ Though I don't see air intake and description is not available on Google Patents

Too many patents for me to guess without a picture, tho perhaps this one: http://www.google.com/patents?id=CB5SAAAAEBAJ&pg=PA1

The company was eventually absorbed by Gardner-Denver (and then Cooper Air Tools)...

There was a  court case in 1923 with Chicago Pneumatic...

Appreciate the responses, here's a picture of it and it is air.

Really a nut runner, but originally advertised as Pnuematic screw drivers.

Probably more like 1950's era...

Iron age: Volume 172 - 1953
"FACTS IN BRIEF ABOUT KELLER PNEUMATIC SCREW DRIVERS Reduce operator fatigue. Interchangeable parts Clutches, socket drivers, 45* and 90* attachments for every purpose Consume less air Need fewer "back-up" parts in the tool ..."

(Sorry, google won't give me a pic)

This eventually became Cleco's specialty...

Yes it looks just like the Cleco nut runners we used when I worked on Aircraft at  the base I was employed at for 29 years they were still in us when I retired from that job in 1993.

ok thanks, a nut runner that helps determine what it is and from the 50's, got it. Thanks for the information gentlemen. Next question, is there even any type of
market for a nut runner like this? I mean, Its old, but probably not old enough.

Is the nutrunner for sale?

Everything has a value - it is usually what someone will pay - but get two old tool nuts bidding against each other in an auction and the prices can get silly....

I buy old tools (mainly billhooks 'serpes') when in France - what I can buy for 1 to 2 euros in a small village 'vide grenier' (flea market) will cost me 5 - 10 euros in a larger 'braderie' in a town. Same tool in a 'brocante' (junk shop) will be about 15 -25 euros - put it in an antiquaire's shop in Paris, and the price will be over 100 euros. I generally buy them on eBay for about 5 to 15 euros, depending if anyone else is bidding.... What then is the true value???? (note in France a new one costs about 30 - 40 euros, so 50% of new price for an old ones does not seem unreasonable if it is in good usuable condition)....

http://www.ebay.com/itm/Lot-of-10-Aircraft-Tools-Cleco-Dotco-Pneumatic-Air-Pistol-Drills-Nut-Runner-/121191867280?pt=LH_DefaultDomain_0&hash=item1c37992390#ht_436wt_642

shows 10 misc air tools for 359 USD - take an average???

The average is $40 which is about 8 times what they are worth IHMO. Air drills have parts that wear and are supposed to be replaced occasionally. But can you still get the parts? doubtfull.

I bought 4 air drills at the flea before I got one that wasn't worn out past salvage....

So, for power tools, there is also the rolling of the dice to take into consideration....