I've sent a letter off to Superior Windmills Co. to see if this is one of their sucker rod wrenches.  I will share the contents with you all.

This wrench is fairly heavy:  3 lbs. 10.5 ozs.

Here's a variation of wrenchmensch's wrench. It's 12.5" long and marked "Superior Nut Washer Wrench"

Same numbers on the movable jaw, too.  Maybe we can find this wrench after all.

A "nut washer wrench" fits a concrete form "taper bolt", apparently an obsolete form tie system...

but i can't find a picture, circa 1978....

How about checking the Concrete Museum's archives?

Quote from: rusty on January 31, 2012, 05:03:13 PM

A "nut washer wrench" fits a concrete form "taper bolt", apparently an obsolete form tie system...

but i can't find a picture, circa 1978....

Whew!  When I first read that I was pretty sure I didn't even want to see the machine you thought it was used on!
Concrete forms have some interesting hardware they use.

Bolt Museum is showing one of these on their What's-It page.

I called the Bolt Museum and got someone who did not know they had a Superior Wrench in the collection.

Here is how concrete forms work today, but I'll bet that the Dayton-Superior name has a history tied to that wrench.
JIS

http://www.daytonsuperior.com/lists/product%20catalog1/download.ashx?ID=2058

Bob,
Have you tried contacting Dayton-Superior? A retired former owner of a bridge construction company was here today and confirmed that the tool was used on concrete forms. He thought he still had a few plus the cone nuts they fit. He was going to try and find them and get back with me. He thought the earliest ones were his Dad's and would date from the 1930's.

Bus,

Sounds like we're on to something!  I appreciate your persistence!   I'll try Dayton Superior per your suggestion. 

Apologies to Geneg who correctly identified this wrench several weeks ago. I wrote to Symons in hopes of getting a picture and story about the wrench.  I spent 6 years in DuPont's Construction Division in the late 1960s, but I wasn't involved in the forms construction side of the business. I was mostly concerned with electricians, pipefitters, weldors, and riggers.