The other day, ToolGuyd described one way of checking the country-of-origin of a pair of soft-handled Vise-Grips. Well, it has come to light (thanks Elroy) that there is a MUCH simpler method that requires simply checking looking at the adjustment screw.
As you can see, on the left we have a pair of Vice-Grips with a clear “Made in USA” declaration, and a completely flat adjustment screw. On the right, notice the absence of any origin info, and a pressure screw that has been machined to accept a 5mm hex key. Looking closely, the knurling also appears to be quite different between the two plier versions. Below is a closeup of the adjustment screws.
This observation was conveyed by Elroy in a GarageJournal forum discussion regarding Vise-Grip origins.