PTO Hammer Mill - $525 (FORT CALHOUN) PTO Hammer Mill. -. $525. (FORT CALHOUN) Wetmore PTO Hammer Mill - "Clipper" Model. This is a big hammer mill, need 50hp+ to run. Used to grind corn and does a great job, only reason for selling is now need to mix with a grinder mixer. Can send video of it running, and it's always been shedded.