Hertel 42221 1/2 Inch Cobalt Screw Machine Drill Bit

Product Description

The HERTEL 42221 is a screw machine length drill bit designed for high-performance drilling in tough materials. Built from M35 cobalt steel with an oxide straw finish, it handles hardened materials, heat-treatable alloyed steels, stainless steel, and titanium alloy without the rapid edge breakdown common with standard HSS bits. The 135-degree split point reduces walking and cutting force at entry, making it well suited for production drilling where accuracy and tool life matter. At 3.75 inches overall length with a 2.25-inch flute, the shortened screw machine geometry provides added rigidity compared to jobber-length bits in the same diameter class.

This bit is used in machine shop, maintenance, and fabrication environments where drilling into hard or abrasion-resistant metals is routine. The 0.5-inch diameter and stiff screw machine length make it a practical choice for drill press, milling machine, and CNC work holding setups. Machinists, tool-and-die workers, and industrial maintenance technicians commonly reach for cobalt bits in this configuration when working with stainless steel components, hardened fastener holes, or aerospace-grade alloys.

Key Features

• M35 cobalt steel construction for extended tool life in hard and abrasion-resistant materials
• 135-degree split point reduces thrust force and minimizes bit walking on entry
• Oxide straw finish provides mild lubricity and heat resistance during cutting
• Screw machine length adds rigidity over jobber-length bits in the same diameter
• Regular spiral flute geometry supports efficient chip evacuation in deep holes
• No coolant-through design — suitable for standard dry or flood-coolant setups

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit for any drill press, milling machine, or CNC spindle accepting a 1/2-inch straight shank bit with standard chuck clearance.

Installation Notes

This bit is installed and used by machinists and maintenance technicians operating drill presses, lathes, or CNC equipment. Secure the shank fully in the chuck and verify runout before drilling. When drilling stainless steel or titanium, use appropriate cutting fluid to manage heat buildup and extend edge life. Inspect the cutting edges for wear or chipping before each use — a dull cobalt bit in hard material generates excess heat and can work-harden the workpiece surface.