What is it used for?

RustyRatRod said
Looks like it might be a bearing scraper.

Bearing Scrapers

I just found out what it is and the sharp edges and fluted surface make since. "WE" were all wrong, but Rusty was close...It's a surface scraper. Found one on E-bay.
Vintage Mound Tool Co Special Scraping Tools Lot Of 6 in Wood Box | eBay