According to a San Francisco State classmate of mine in the early 1970s, who worked for Thorsen in Emeryville, Thorsen's plant was very much worn down and dragged out when Thorsen won the contract to make PowrKraft tools for Montgomery Ward in 1970 or so. He also said that Thorsen was probably the last commercial maker of flat wrenches in the U S to forge wrenches one end at a time, and that this explained why same-part-number Thorsen wrenches varied so much in length . . . the blank length for any given run could be adjusted to get an extra wrench or two out of each 20-foot "stick" of barstock if necessary, and sometimes the last piece of the bar was of a different length than the previous pieces.
Thorsen was also unusually casual about slipping Thorsen-branded tools into Action (Thorsen's economy brand) and private-label-branded tool sets, even after the Dallas plant was operational. I bought Powr-Kraft socket and combination wrench sets in the early 1970s that contained several Thorsen-branded tools, and a set of Action 3/8 inch drive metric sockets (according to the hang card) in the late 1970s containing ONLY Thorsen-branded sockets. Other-label tools in Thorsen sets seemed to me to be rarer, but not unknown.
Also in the late 1970s, I bought a Herbrand 1/2 inch drive, 7/8 inch hex deep socket (again, according to the hang card) that was, in reality, an aircraft spark plug socket that had been double-stamped with both the Bonney and Thorsen names. When I noticed the erroneous markings, I went back to the store (a Gibson's discount store) and checked the remaining stock. No more double-stamping, but the half-dozen or so sockets on the peg were marked either Bonney or Thorsen.
It's pure speculation on my part, but I suspect that Triangle Tool (Bonney's parent company) subcontracted non-cataloged aircraft spark plug sockets to Thorsen, which shipped a mixture of Bonney-branded and Thorsen-branded sockets that, for some reason or another, Triangle decided to get rid of by packaging them under the name of their economy line, Herbrand.
I'll also speculate on the Kraeuter-branded combination wrench discussed earlier. By the late 1970s, Kraeuter was Dresser Industries' economy line of wrenches and sockets. Kraeuter-branded sockets and drivers were obviously badge-engineered S-Ks, but the flat wrenches were from distinctly different forgings. S-K flat wrenches of the time had "raised panel" shanks, the Kraeuter flat wrenches flat shanks. It seems entirely reasonable to me that Dresser / S-K might have contracted production of the Kraeuter-branded flat wrenches (and subcontracted production of Klein-branded flat wrenches, which Klein had contracted to Dresser / S-K) to Thorsen.
Next, after Dresser Industries sold their S-K Hand Tool business to Facom, in the early 1980s, S-K introduced a short-lived line of economical S-K branded tools that were generally stamped only with their size and an S-K-in-diamond brand. The economy model S-K ratchet was obviously a cross between a Facom mechanism and an S-K "Professional" ratchet body (These ratchets are relatively rare, and are often spoken of as the S-K Frankenstein ratchet because the shifter and pawl are combined into a side-to-side sliding bolt through the neck of the ratchet.) The sockets S-K supplied in the sets containing these ratchets were visibly different than their Chicago-made sockets (which were mostly still being screw-machined and broached), looking for all the world like the cold-formed sockets Thorsen manufactured in Dallas.
Still more . . . years ago I ran across a newspaper article that reported that Thorsen Tool had been unable to fulfill a U S government contract for sockets due to "teething pains" with their new manufacturing equipment, and that the government was forcing Thorsen to purchase sockets from other makers, at higher prices than Thorsen was selling them to the government, to meet their contractual obligation. I would not be surprised if the government's action was the proverbial "final straw" for Thorsen.
Finally, I have wondered for years if the Thorsen's Dallas plant became, after Thorsen's demise, the National Hand Tool Dallas plant that made Blackhawk-branded and Husky-branded mechanics tools after New Britain Machine sold off their tool business and shuttered the (North or South, I forget) Carolina factory.
