Wm HJORTH & CO
from Alloy Artifacts: (also photo)
"The company was apparently in operation by 1903, based on a notice for the "Empire" pipe wrench published in that year.
[1904 Advertisement for Wm. Hjorth & Company]
Fig. 196. 1904 Advertisement for Wm. Hjorth & Company. [External Link]
Fig. 196 shows an ad for several of the tools offered by the Hjorth company, as published on page 547 of the July, 1904 issue of the Hardware Dealers' Magazine.
The illustration at the top shows a "Lightning Wrench", a plier-wrench combining pipe and nut gripping surfaces. The patent date on the tool refers to patent 738,444, filed by A.W. Hjorth in 1902 and issued on September 8, 1903, with assignment to William Hjorth & Company.
The middle illustration shows the "Empire" pipe wrench, with a patent date referring to patent 735,289. This patent was filed by Karl Peterson in 1902 and issued on August 4, 1903, with assignment to William Hjorth & Company. (Karl Peterson went on to become the founder of the Crescent Tool Company.)
Finally, the bottom illustration shows a pair of combination pliers.
The advertisement was placed by Wiebusch and Hilger, acting as manufacturer's agents for the Hjorth company.
A similar reference can be found in the January 18, 1905 issue of The Horseless Age, which notes Hjorth as the maker of a "Lightning" plier wrench, an "Empire" pipe wrench, and combination pliers."