01M551 - Walter SST+ 51/64" Cobalt Prentice Drill Bit with 1/2" Shank

Heavy-Duty Drilling Performance with Walter SST+ Technology

The Walter 01M551 SST+ Prentice Drill Bit is a high-performance cutting tool engineered for industrial maintenance, repair, and operations (MRO) professionals who demand reliability and precision. This 51/64-inch drill bit is part of the renowned SST+ series, which is celebrated for its ability to tackle the toughest materials found in modern manufacturing and fabrication environments. Unlike standard high-speed steel bits, the SST+ line is manufactured with a proprietary cobalt blend. This advanced material composition provides exceptional heat resistance, allowing the bit to maintain its hardness and cutting edge even when subjected to the high temperatures generated during heavy-duty drilling applications.

One of the standout features of this specific model is its "Prentice" style design, commonly referred to as a reduced shank bit. While the cutting diameter is a substantial 51/64 inches, the shank is precision-machined down to 1/2 inch. This critical design element allows operators to drill large-diameter holes using standard portable power drills, drill presses, and magnetic base drills that are limited to a 1/2-inch chuck capacity. This versatility eliminates the need for specialized heavy machinery for mid-sized hole creation, making it an indispensable tool for field work and shop floor maintenance.

Efficiency is at the core of the Walter 01M551's design. It features an exclusive self-centering 135-degree split point geometry. This aggressive point angle ensures that the bit bites into the material immediately upon contact, effectively eliminating the "walking" or wandering often associated with standard drill bits. Furthermore, this geometry removes the need for pre-drilling pilot holes, significantly reducing cycle times and increasing productivity. To address the common issue of bit slippage under high torque, the shank is engineered with three ground flats. These flats provide a positive lock within the chuck jaws, ensuring maximum power transmission from the drill motor to the cutting edge.

Finished with a special bronze SST surface treatment, this drill bit not only cuts faster but also evacuates chips more efficiently, preventing clogging and heat buildup. Whether you are working with mild steel, non-ferrous metals, or challenging stainless steel alloys, the Walter 01M551 delivers consistent, round, and burr-free holes, making it a top choice for professionals seeking longevity and performance.