Gripping Tales: DC K36 pliers, Duluth, Minnesota

I suspect that these may be a product of the Diamond Calk Horsehoe Company, before it became the Diamond Tool & Horseshoe Company.  That's because the later company was located in Duluth and used a diamond in its trademark.  They also bear the same pattern on the handles and the "K" model designation shown on Diamond Tool pliers on the Alloy Artifacts page.