Hertel 42217 Cobalt Screw Machine Drill Bit 31/64 in

Product Description

The HERTEL 42217 is a cobalt screw machine length drill bit designed for drilling into hard and demanding workpiece materials. Built from M35 cobalt high-speed steel, it carries an oxide straw finish and features a 135-degree split point that reduces walking and allows cutting to begin without a center punch. The spiral flute geometry handles chip evacuation efficiently during short-hole drilling operations. At 3.6875 inches overall length with a 2.1875-inch flute length, this is a stub-length bit engineered for rigidity and reduced deflection in production and maintenance machining environments.

This bit is suited for drilling hardened materials, heat-treatable alloyed steels, stainless steel, and titanium alloy. The screw machine length profile makes it a practical choice in drill presses, CNC machining centers, and hand-held power drills where clearance is limited and a shorter, stiffer bit is preferred over jobber length. The 31/64 inch diameter places it in common use for close-tolerance hole sizing prior to reaming or tapping in fabrication and maintenance applications.

Key Features

• M35 cobalt construction for heat resistance and extended tool life in hard materials
• 135-degree split point reduces thrust and eliminates center-punch requirement
• Oxide straw finish provides light lubricity and corrosion resistance
• Screw machine (stub) length increases rigidity and reduces deflection versus jobber bits
• Regular spiral flute supports efficient chip clearance in short-hole drilling
• No coolant-through design — compatible with external cutting fluid application

Compatibility

Designed as an OEM-style replacement or direct-use cobalt drill bit for applications requiring a 31/64 inch diameter screw machine length bit rated for hardened materials, heat-treatable alloyed steels, stainless steel, and titanium alloy. Fits standard drill chucks accepting round-shank bits in the 0.4500 to 0.5000 inch diameter range.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician. Secure the bit firmly in the chuck and verify concentricity before operation. Apply an appropriate cutting fluid externally when drilling stainless steel, titanium, or hardened alloys to manage heat buildup and extend tool life. Inspect the cutting edges for wear before each use and replace the bit if the split point or cutting lips show chipping or burnishing.