01M618 - Walter SST+ 1-3/8 Inch Reduced Shank Cobalt Drill Bit

Industrial-Grade Large Diameter Drilling Solution

The Walter 01M618 SST+ 1-3/8" Prentice Drill Bit represents a pinnacle in heavy-duty hole making for maintenance, repair, and fabrication environments. Engineered by Walter Surface Technologies, this bit is part of the renowned SST+ series, specifically designed to address the challenges of drilling large diameter holes in tough materials like stainless steel and other ferrous alloys. The "Prentice" designation refers to its reduced shank design, which steps down the 1-3/8" cutting diameter to a standard 1/2" shank. This critical feature allows operators to utilize large-capacity bits in standard portable drills, magnetic drills, and drill presses that are limited to a 1/2" chuck capacity.

Metallurgically, the 01M618 is constructed from a premium cobalt blend High Speed Steel (HSS). This composition significantly enhances the bit's red hardness, allowing it to maintain a sharp cutting edge even at the elevated temperatures generated when drilling large holes in hard metals. To further augment performance, the tool features a specialized Bronze SST surface treatment. This treatment reduces the coefficient of friction between the tool and the workpiece, facilitating smoother chip flow and reducing heat buildup, which is the primary cause of premature tool failure.

Operational efficiency is maximized through Walter's exclusive point geometry. The bit features a self-centering 135° split point that bites into the material immediately upon contact, effectively eliminating the "walking" phenomenon common with standard bits. This removes the necessity for pre-drilling pilot holes or using center punches, thereby streamlining the workflow. Furthermore, the shank is machined with three distinct flats. These flats ensure a positive lock within the drill chuck, preventing the bit from spinning under high-torque loads—a common issue when drilling large diameters in high-tensile materials. For industrial professionals requiring precision, durability, and compatibility, the Walter 01M618 is the definitive choice.