My father and grandfather both spent their entire working careers at Allis Chalmers in West Allis, Wisconsin. This is a neat postcard showing the plant circa 1911. That was well before they worked there, but the core buildings were the same.
The street in the foreground is South 70th Street, and the street to the right is West Greenfield Avenue,
The postcard is franked with a one-cent Franklin. It's either US Scott 331 or 374 depending on the watermark. I suspect #374 given the May 28, 1911, postmark.
I can find lots of information on the recipients, Stanley and Lillie Whallon of Ohio, but not on the sender, Gilbert Jackson. He shows up in the 1911 Milwaukee City Directory, occupation machinist, but that's about it. I'll keep searching.
The Acmegraph Co. was a Chicago-based postcard publisher and printer that was in business from 1908 to 1918.