He was a mentor to Jody Samson and made knives for over 60 years. Cooper began making utility knives and butcher knives in Tremont, Pennsylvania in 1924 while working as a welder. Eventually he moved on to welding in the Virginia shipyards and began making hunting knives, fishing knives and combat knives as a second business.
As a full-time knifemaker, he noticed that his traditional methods of knife making could leave gaps between blade, guard, and handle material where water or blood could collect and eventually corrode the knife.
He developed a new method of construction which made the knife and handle into a solid, bonded unit by welding, brazing, and using epoxy. He patented these ideas in 1967 (3481038) and 1971 (3595104).
A prolific maker who made over 100 knives in a month, Cooper taught his trade to knifemakers, Jody Samson and Vic Anselmo in 1969. Cooper made push daggers for police officers and Federal Bureau of Investigation agents.
Celebrities such as John Wayne, Sammy Davis Junior. and Lee Marvin collected Cooper"s knives.Cooper made knives used in film and television such as the Arkansas toothpick in The Sacketts and a Bowie knife for Jeremiah Johnson.
In 1978, Cooper opened a new knife shop in Lufkin, Texas where he made 1,000 knives per year until his retirement from knifemaking in 1981. In retirement he made a few knives every year until his death in 1987.