I cannot find a date stamped in the slide key, so information on the internet indicates it may be from 1941 to 1944. I don't know but other information with the Wilton name & Chicago USA on both side of the main body also indicate it may be from that time period.
Both sides of the main body say " Wilton Chicago USA ". The maximum jaw spread looks to be a comfortable 5. The item "VINTAGE WILTON Early 3 BULLET VISE SWIVEL BASE MACHINIST MECHANIC TOOL VISE" is in sale since Monday, October 21, 2019. This item is in the category "Collectibles\Tools, Hardware & Locks\Tools\Carpentry, Woodworking\Vises, Clamps".The seller is "chief_z_sales" and is located in Mason City, Iowa. This item can be shipped to United States.