A Closer Look at the Blade

The challenge in making the best screwdriver blade is achieving the strength of a relatively high hardness (resists bending and twisting) without becoming brittle (causes breaking of fine tip geometry). To do this, we use AISI 8650, an alloy steel with the right amount of carbon (0.48-0.53 %) for hardenability and the elements nickel, chromium, and molybdenum to aid in machining and preventing brittleness. Through a carefully controlled heat treating process, blades reach a hardness of HRC 52-56. The result is a tough blade that resists bending along the shaft, twisting at the tip, and is durable enough to maintain tip geometry over time.

To prevent rust, the steel surface of the blade is treated with a hot black oxide finish—the same process used to protect firearms. This process is a controlled oxidation of the actual surface of the steel (called a conversion process), resulting in a thin layer of magnetite. This kind of finish prevents rust largely through its ability to absorb and hold a topcoat like oil or wax, creating the barrier between water and raw steel that prevents rusting. To maintain full protection over time, it’s important to periodically apply a thin coat of light machine oil to each blade with a cloth.