I'm working on an Airking Premier (close to 700Lw) maybe.
http://www.nostalgiaair.org/PagesByModel/398/M0000398.pdf
The volume control adjusts the 6d6 RF amp.
The pot wiper went to one side of the line switch and the other side has the power cord.
I was going crazy trying to figure out how the line switch was working because it did not have any leads going to the chassis. So I finally removed it to test it and found that the case of the pot/sw is itself grounded by being screwed onto the chassis.
One side of the swith is common with the shaft and case assembly!!
Was this ever a common practice back then?

Took a look at the schematic. It looks like it was designed that way. Looks like it would make a good hand warmer. Don't play it while standing in a puddle. I have a radio that appeared in a Hugo Gernsback magazine in the early thirties (I think it was Radio Craft). It was a ac/dc line cord resistor type radio with four tubes. In the article they showed it as a bathroom radio. As always safety first. See ya
MRO

Interesting, both Mark and Peter. Regarding the switch, I don't think that the design is all that common. I have a Philco 60 whose "low" leg of the volume control is connected to the chassis through the case. I don't know if this pot. is original or not. Looks to be about as old as the radio. However, before I took everything apart, it looked like the wires were soldered to clipped off terminals from another pot., which were in turn soldered to this pot. Could have even been a factory swap. There is no evidence of a third wire, so perhaps the chassis connection was always made through the control case.

Interesting little things.

Thomas

It is hard to say what has been done to a radio that has survived for 70 or more years. I have come across pots that have simular grounding arrangements. Some of those depression era radios can have some unique designs.
MRO

Well as far as I can determine this an original pot/switch.
I wanted to see the inside.. so I tried to open it, but after the tabs were lifted I saw that the case is held under the brass threaded thingie which is held on the shaft by a c-clip in a groove on the shaft. I couldn't get that to release so I gave up.
I soldered a wire anyway on the switch to ground so the next guy won't get confused... but it may confuse him more. lol
Any way I put a nice new polarized safety cord on it with the ground lead to the switch.
Sometimes I get lucky and find extension cords in the $1 store and cut the recptacle off.
But now..
I get these nice cords for a $1 each (10 in a pkg for $10) from National Artcraft that I found via amazon.com.
6 ft. brown, ploarized plug, striped tinned leads.

http://www.amazon.com/gp/product/B0007GFBCO/qid=1141282555/sr=1-5/ref=sr_1_5/002-2513328-6493627?%5Fencoding=UTF8&v=glance&n=1064954

Thanks, Peter, for the line cord tip. I just ordered 20 of them there boogers. @ $1.00 (plus shipping), they're cheaper than buying a polarized plug and adding my own lamp cord.

You're welcome Doug:

Every now and then I hit upon a nice fid. Another great find is the resistor kits I bout for $15 each. Great... I bought the 1 watters but the others are even cheaper.
You get 10 of each vaule and 24 values per kit. They are in nice little marked drawers .. even has a tweesers to pick them out with. I got 2 sets the 1st goes from 2.2 ohms to 2.7k the 2nd set goes from 3.3k to 10 meg.
These are so nice and bargain priced too!
http://www.goldmine-elec-products.com/products.asp?dept=1128

The next nice find is:
pilot lamps... #47s or #44s.. and others...I get them 10 in a box for $1.. how can you beat that??
Pinball life
http://www.pinballlife.com/index.php?p=product&id=19&parent=3

enjoy...

Thanks Peter, cords and the lamps, bet there's a run on those cords. Now can you find NOS 45s at those prices