ATS-55 Steel Profile

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ATS-55 is a stainless blade steel associated with older Spyderco knives. If you are looking at one today, the exact knife and its condition deserve more attention than a modern steel ranking. It is a distinct grade, not another name for ATS-34.

What Is ATS-55?

Spyderco founder Sal Glesser identifies ATS-55 as a steel made by Hitachi exclusively for Spyderco. It was developed for knives. The chemistry here is Spyderco’s knife-maker reference rather than a melt certificate for a particular blade.

ATS-55 Is Not ATS-34

The similar names make this an easy mix-up. Spyderco’s reference lists 0.6% molybdenum for ATS-55; its ATS-34 entry lists 4%. That difference establishes that they are separate recipes, but it does not give us a measured edge-retention or toughness comparison. Check the blade marking rather than borrowing specifications from an ATS-34 listing.

Looking After an Older ATS-55 Knife

Inspect the cutting edge for chips and uneven sharpening before deciding how much work it needs. A blade that has been sharpened heavily may cut differently from its original shape. Clean and dry stainless blades after wet or salty use, and keep sharpening suited to the edge: serrations need an abrasive that fits their shape.

What Matters When Buying ATS-55 Today?

For an older folder, clear photographs of the blade marking, tip, edge and handle are more useful than a seller’s claim that the steel is rare or premium. Check the action and lock as well as the blade. Buy the model you want in a condition you understand; an alloy name alone cannot establish collector value or the remaining life of a used knife.