Similar to a Brown Manly 1AA only a hair bigger. Marked A.

One sold several years ago in one of the York auctions;  provenance unknown, but a tentative "Minnesota?" guess guess was included in the listing.  It is roughly 6 1/2" overall length.

I've got nothing. I guess it is an orphan.

Bus.. This wrench looks exactly the same as the ACME you hsve on your sold page. Different marking. Any chance of a connection?