01A517 - Walter SST+ 17/64 Inch Cobalt Blend Jobber Drill Bit

Technical Overview of the Walter SST+ 17/64" Drill Bit

The Walter 01A517 is a high-performance 17/64-inch drill bit from the renowned SST+ series, engineered specifically to address the challenges of drilling high-tensile strength materials. At the core of this tool is a proprietary cobalt blend high-speed steel (HSS) substrate. The addition of cobalt significantly increases the red hardness of the bit, allowing it to maintain its cutting edge integrity at the elevated temperatures generated when machining stainless steel and other hard alloys. Unlike standard black oxide bits that soften under thermal stress, the SST+ composition ensures consistent hardness and durability throughout the drilling cycle.

Geometrically, the bit features a precision-ground 135° split point. This specific angle serves two critical technical functions: it reduces the thrust load required to penetrate the workpiece, and it provides self-centering capabilities. This eliminates the need for center punching, even on curved surfaces or pipes, thereby improving process efficiency. The body of the bit is fully ground, ensuring tight concentricity tolerances for accurate hole sizing.

A distinguishing feature of the SST+ line is the "High Flow" flute design. In deep hole drilling or hard metal applications, chip packing is a primary cause of tool failure. The High Flow geometry optimizes the helix angle and flute width to rapidly evacuate swarf from the cutting zone. This rapid evacuation prevents heat buildup and reduces the risk of work hardening the material—a common issue with austenitic stainless steels. The tool is finished with a special bronze SST surface treatment, a tempering process that relieves internal stresses and reduces the coefficient of friction between the tool and the workpiece.

This drill bit is rated for use on a wide spectrum of materials, including mild steel, non-ferrous metals, and stainless steel, making it a versatile component for industrial MRO inventories. It is compatible with both stationary machine tools and portable power drills.