Dating presto jars
The standard thinking was that Ball dropped the Automatic Sealer line of jars after they acquired Schram, but continued to use the Drey molds at the old Schram plants over the next few years until they wore out.A few Drey molds were even known to have been modified, the "Drey" being changed to read "Ball." The Ball Square Mason jars are one example.Leo Drey, who pronounced his last name dry, was the president of the Schram Manufacturing Company from 1908 until his death in 1920.
The number has nothing to do with when the jar was made.
But not all can be found with a full-wire bail closure, a patented circular dimpled boss, and both shoulder seal and bead seal mason closures.
The embossing variations include Drey Ever Seal, Drey Improved Ever Seal, Drey for many years.
Ball bought the rights to the grippers from Brockway in 1933, eight years after acquiring Schram. of December 1991: "Ball Muncie Production journals show that Ball produced various styles of Drey jars as late as 1938 - thirteen years after they had bought Schram....
It is unknown why Ball continued to make competitor jars long after having acquiring them." the discovery a cardboard box labeled Drey Perfect Mason.