Not a wrench, but....

[Northwoods]

Picked up a Snap-on 7" awl in pretty nice condition yesterday.
Translucent amber squarish hollow handle, marked Snap-on (underlined) C7-4B Pat. No. 201171.   
Applied in '61; granted in '65
I can't find anything about it on the Interweb
Is it a short run item? And what is with the hollow handle?  Should there be a plug in the end?

[Bill Houghton]

Is the awl part fixed into the handle, or is there a (probably knurled or hex) collar where it meets the handle?  If there is a collar, it's probably a multi-tool, with a number of different tools to slot into the handle (screwdrivers, pry bars, etc.; some of the really cool ones had chisels and gouges), of which only the awl survived.   The tools would fit into the hollow handle, and the missing plug would, of course, keep them there.

I've had a Snap-On magnetic hex driver with a hollow handle to hold more bits; on that one, the opening where the plug would have gone, had it not run away to join the circus, was threaded.

Here's an example of what I mean:

[couchspring]

Is it threaded for a cap? Maybe it is a 12 volt test light with missing parts.

[amecks]

+1 .....Test light.  I have one at home and can check the part number.  The patent #210171 is a Design patent for the handle.
Al

[Northwoods]

This puppy is amber plastic. The blade is permanently fixed.  The hole is not threaded, and is 1/2" by 2 1/2".
Curioser and curioser.

[eddie hudson]

Go to collectingsnapon.com and start reading the 1960's catalogs.

[Bill Houghton]

If it's a 12 volt test light, the metal shaft should stick into the hollow of the handle, or at least be exposed at the bottom of the hole.

Waiting to find out what this is; interesting.

[Northwoods]

Well, you guys had it exactly right.  It is a circuit tester.
Found it in the 1967 catalog, page 95.
The problem was that I had misread the part number as C7-4B when it is actually CT-4B.
Circuit tester (CT  )
Found similar ones with similar numbers back to '61, but this exact one showed up in '67.
As Inspector Jacques Clouseau would say, "The mystery is solved!"

[amecks]

Yes.  I went out to the garage and found mine - it's a CT4C.   Mine was in the same condition as yours - no innards.  I took a clevis pin that fit the handle hole perfectly and ground it to length til it just touched the metal shaft.  The clevis pin head sticks out the top flush with the handle.  Maybe I used epoxy to secure it - I can't remember.   Makes a good solid tool.  (I don't actually hammer on it much but it does get used occasionally to line up holes or punch holes in softer materials).

It would be easy enough to rebuild it as a tester - bulb and a coil of wire wrapped around it and connected at the top to a flexible wire.  The "cap" in the original tool is a cord grommet like on the back of appliances - should be easy to find one.

Al

[Northwoods]

I plugged mine with a hardwood cap.
I originally mistook it for an awl.  Well, it's an awl now!

[Bill Houghton]

I plugged mine with a hardwood cap.
I originally mistook it for an awl.  Well, it's an awl now!

https://www.youtube.com/watch?v=gBzJGckMYO4

[Northwoods]

Bill H:     Grooooooooan