Why so thick?

[HeelSpur]

This was in a box and was pretty rusted up, it has no markings what-so-ever.
What job would require a wrench so thick?

[Lostmind]

Water valve / hydrant?

[HeelSpur]

Water valve / hydrant?

Don't know, maybe its made out of cheap metal.

[john k]

I would say strength.   I don't see a lot of early open end wrenches that aren't spread, oversize at the jaws.    The metallurgy just wasn't there yet, in the early 20th century, so to make them stronger they made them either thicker or beefier around the jaws.  It looks like a valve wrench, gas, water?  to me.

[wrenchguy]

The wrench in question is somewhat modern, not forged, thus thicker 4 strength.

[rusty]

It is a tool post wrench , in pattern. Perhaps for some machine that need a cheap wrench for only occasional adjustment, like a drill press...

Perhaps not as moders as you might think, The open end of a toolpost wrenche generally are parabolic rather that v-notched by the 1940's. however, stamped wrenches are not completly consistant in that, they were often a bit simplistic in design. (even modern stamped bicycle wrenches often have poorly designed openings in them - poor because the v-notch tends to split and crack)

The odd thing is I have never seen any of the normal stamped steel wrench makers showing tool post patterns....

[johnsironsanctuary]

How about a one time use installation tool? Door closer?

[Nolatoolguy]

Maybe they only needed a few. Could it be that was scrap steel and they didn't want to order steel for just a few wrenches.

Hmm, that still seams weird.