Hertel 42150 Cobalt Jobber Drill Bit 9/32 Inch

Product Description

The HERTEL 42150 is a cobalt jobber-length drill bit designed for drilling stainless steel, hardened materials, and other tough alloys that wear out standard high-speed steel tooling. Built to M35 grade cobalt specification, this bit features a 135-degree split point that self-centers on contact and reduces the thrust required to start the hole. The straight-shank, right-hand spiral design is compatible with standard drill chucks. At 4.25 inches overall length with a 2-15/16-inch flute, this is a general-purpose jobber format suited for production and maintenance drilling where bit longevity under heat and abrasion is the primary concern.

This bit is a go-to for maintenance technicians, fabricators, pipefitters, and metalworkers who regularly drill into 300-series and 400-series stainless steel or similarly abrasion-resistant materials. The 5xD flute-to-diameter ratio provides adequate chip clearance in moderate-depth holes. The oxide finish on the flutes helps resist heat buildup during prolonged cuts. It does not support coolant-through delivery, so external cutting fluid or cutting oil should be used when drilling stainless to extend tool life and prevent work hardening of the material.

Key Features

• M35 cobalt steel construction handles stainless steel and hardened materials without rapid edge breakdown
• 135-degree split point self-centers and reduces walking on smooth or curved metal surfaces
• Right-hand cut with regular spiral flute for standard drill press and hand-drill applications
• Straight cylindrical shank fits standard three-jaw drill chucks without an adapter
• Oxide finish on flutes provides additional heat and corrosion resistance during dry or lubricated drilling
• Heavy-duty grade rating appropriate for production use and repeated service in tough materials

Compatibility

Designed for use in standard drill presses, magnetic drills, and hand drills equipped with a chuck accepting straight-shank bits in the 9/32-inch size. Primary workpiece materials are stainless steel and hardened metals.

Installation Notes

Secure the bit fully in the chuck before drilling and verify runout is within acceptable tolerance to prevent premature edge wear. Apply cutting oil or a sulfurized cutting fluid when drilling stainless steel to prevent work hardening and extend tool life. Reduce feed pressure as the drill breaks through to avoid grabbing. Inspect the cutting edges before each use and replace the bit if chipping or dulling is evident, as a dull cobalt bit on stainless will harden the workpiece surface and make subsequent drilling more difficult.