O1 Tool Steel for Knife Blades

AISI O1 Tool Steel

Manufacturer: Various

O1 is a useful oil-hardening knife steel that has some Vanadium in it as well as fairly high Carbon content. It has very little Chromium and is less tough than comparable tool steels such as 52100. Typically O1 can be hardened to about RC 65, though in production models it is sometimes hardened to the mid 50's.

O1 is commonly found in woodworking tools as well as damascus steels. O1 is occasionally seen in production knives and is also occasionally used by custom knifemakers for medium-sized fixed blades. O1 is popular with custom makers that like to differentially harden their blades as well. O-1 has very little corrosion resistance so care must be taken to ensure that your O1 knives do not rust.

Some production companies uses O1 include Randall Made Knives and Mad Dog.

Latrobe Specialty Steel O1 Data Sheet PDF


C Co Cr Mn Mo Ni P Si S Cu V
0.85-1 - 0.4-0.6 1 - 0.3 - 0.5 - - 0.3
Values are shown in percentages.