What Are The Greco Tang Numbers

[hso]

Does anyone know what the numbers on John Greco's knives mean? A buddy has a "1". I've got a "2" and a couple of "5"s.

 

[not2sharp]

The numbers indicate the type of steel used. "5" was 5160, "A" was A2, and "1" may have been 1095 (?).

n2s

 

[Chiro75]

"1" is one of three possible steels: 1075, 1084 or 1095.
I've never seen one marked "2" although he supposedly uses 52100 on some knives, so that could be the "2" since "5" is already used for 5160. Unmarked knives are 8670. "A" is A2. Everything I've ever owned from Greco has been "1" for the small knives and "A" for the big knives.