In the knife industry a “mule” is a sample knife used for performance testing. Spyderco’s Mule Team Series takes this concept a step further by offering the same fixed-blade knife pattern in many different steel variations. This ongoing project allows steel-obsessed knife enthusiasts a unique opportunity to test and evaluate different steels using the same identical design platform. Mule Team blades are furnished without handles or sheaths and are also popular “kit” blades for aspiring knifemakers and hobbyists.

Spyderco’s twenty-seventh Mule Team installment features Carpenter® steel's Micro-Melt® PD#1 alloy—an air-hardening cold-work die steel. PD#1's unique alloy composition gives it wear resistance significantly superior to conventional steels like D2, while still maintaining excellent toughness. Thanks to Carpenter's advanced Micro-Melt powder metallurgy process, PD#1 possesses an extremely fine microstructure and uniform carbide distribution, as well as the enhanced compressive strength necessary for the demands of tooling applications. Collectively, these qualities give it a unique combination of wear resistance and toughness that make it ideal for use as a blade steel.

PD#1's unique alloy composition includes: 1.1% Carbon, 7.75% Chromium, 1.2% Silicon, 1.6% Molybdenum, 1.1% Tungsten, 0.25% Manganese, and 2.35% Vanadium. Note that its moderate Chromium content provides only limited corrosion resistance, so please maintain your knife properly.