[GreenKeys] Why the "Can" in Can Wrench

[Steve Hilsz]

I am forwarding an excellent explanation of the origin of "Can" in "Can 
Wrench," as posted by Paul Hoffman on the Telephone Collectors International 
(TCI) listserv:

More than anyone other than a TCI member wants to know about using can 
wrenches. If you aren't interested hit delete now before being too bored. To 
many readers what's below may be old news and "duh...". But others, 
especially those who are collectors but not former telephone workers, may be 
interested in some more arcane trivia about the can wrenches.

The old can wrenches were NOT solid units (like later ones), they were a 
combination screwdriver & socket wrench. The glass middle section (in really 
old ones brown non-metallic middle section) had posts out each end, that 
actually ended in flat-bladed screwdriver ends deep within the sockets. The 
'socket wrench' part was spring held firmly in place so normally it would 
work like a solid unit and just as a wrench...you might not even realize 
there was a screwdriver blade buried inside the wrench part. But you could 
also unlock the socket from the handle-and-screwdriver, so the wrench and 
embedded screwdriver could operate independently.

Many of you are familiar with the old porcelain or Bakelite protectors that 
had long fuses...each of which had a threaded end and a nut, to hold them in 
place on the protector. Can wrenches were used to loosen and tighten these 
nuts when you wanted to replace a blown fuse...or in later years, to strap 
the fuses out when on-site doing anything else, while you were there (to 
eliminate blown fuse troubles in the future, without having to swap out the 
protector to a newer style.)

Where the screwdriver-in-the-can-wrench came into play was to install or 
remove similar fuses in old fuse protected inside terminals. ISTR that those 
fuses were slightly different. The end that screwed into the rear of the 
terminal was threaded, but without a nut. And it screwed into a threaded 
hole in the rear conductor. The end of the fuse that was attached to the 
front of the terminal was threaded with a nut, but the end of the threaded 
section was notched for a flat bladed screwdriver.

This allowed you to hold the fuse itself steady with the embedded 
screwdriver while using the wrench to unlock/loosen the nut...if you didn't 
hold the fuse steady with the screwdriver, if you used a wrench on the nut 
you were likely to twist the entire fuse and pretzel the conductor strip the 
nut was locked to. By holding the fuse steady with the screwdriver part, you 
were putting torque against the screwdriver instead of along the whole fuse. 
Once you had loosened the nut with the wrench, you then spun the handle and 
screwdriver part to back the rear end of the fuse out of its threaded hole.

I used to run into these old long-fuse-equipped inside terminals on a 
regular basis when working the older sections of Passaic NJ in 1971. (Many 
were also equipped with the shorter 'sneak current' fuses as well.) I don't 
think I ever saw one again when I transferred to CA in 1972 ... but I was 
working then in a suburban rather than old urban area, Walnut Creek, Orinda, 
Lafayette, and Moraga (mostly) in the East Bay area due east of San 
Francisco and Oakland. I would not be surprised if the same old fuse 
equipped terminals were still around in SF or Oakland, but that's not where 
I was working.

Another piece of old lore: Sometimes you'd run into a broken can wrench, 
where it had been dropped and the glass center section had broken. I'd carry 
one of these around to use just like a stubby screwdriver, for those cases 
when I'd run into a protector can that didn't have sufficient clearance 
below to use a standard can wrench on its nut. Sometimes remodeling on the 
outside of the house had reduced clearance...For whatever reason I don't 
remember usually having an adjustable wrench with me, and it was easier to 
use a stubby can wrench than try to mangle the nut loose with a pair of long 
nose.

I remember the first time I saw someone with a 'new' can wrench...one that 
was solid and the same diameter the whole length, with just the metal can 
wrenches at its ends. My first reaction was "that's stupid, how will you 
deal with the terminal fuses?" My second reaction was that it had been maybe 
15 years since I had run into a terminal fuse as described above, so maybe 
it wasn't that big a deal after all. :}

I'm sure many of the long term TCI contributors may be able to tweak what 
I've written here and there....but that's how I remember the old fuse 
equipped terminals being setup, and why can wrenches were really combination 
wrench/screwdrivers.

Paul H. (forwarded by Steve Hilsz)