Hertel SDD43274570 Step Drill Bit Cobalt 7/8-1-1/8 in

Product Description

The HERTEL SDD43274570 is a cobalt step drill bit designed to drill and ream two hole sizes in a single operation. The bit features a 3/8 inch round shank with three flats for secure chuck engagement and reduced slippage under load. It steps from a minimum hole diameter of 7/8 inch up to a maximum of 1-1/8 inch, with a 1/8 inch step length between sizes. The bright, uncoated finish suits general-purpose drilling in steel, sheet metal, stainless, and other ferrous materials. At 0.287 pounds, it is lightweight and well-balanced for extended use. Electricians, plumbers, HVAC technicians, and fabricators commonly reach for this type of bit when punching clean, accurate holes in enclosures, panels, and conduit plates.

This step drill bit is suited for trade and light industrial applications where two incremental hole sizes are needed without a tool change. Common scenarios include drilling knockout holes in electrical enclosures, sheet metal HVAC panels, and plumbing access plates. The cobalt construction handles higher heat and harder materials than standard high-speed steel, making it appropriate for intermittent use in stainless steel and hardened sheet stock. Packaged as a single unit, it fits standard 3/8 inch and larger keyed or keyless chucks.

Key Features

• Cobalt tool material for improved heat resistance and longer tool life in ferrous and hardened materials
• Steps from 7/8 inch to 1-1/8 inch — two hole sizes in one pass
• 3/8 inch round shank with three flats prevents rotation in the chuck
• 1/8 inch step length for controlled, incremental material removal
• Bright uncoated finish — ready to use out of the package, no coating to chip or flake
• Weighs 0.287 pounds — compact and easy to handle in tight spaces

Compatibility

Designed for use in standard 3/8 inch and larger keyed or keyless drill chucks. Suitable for drilling sheet metal, mild steel, stainless steel, and similar ferrous materials in electrical, HVAC, plumbing, and light fabrication applications.

Installation Notes

Step drill bits should be installed by a qualified tradesperson familiar with proper drilling technique for the material being worked. Always secure the workpiece before drilling and use appropriate cutting fluid when drilling stainless steel or hard alloys to extend bit life and prevent work hardening. Power down the drill and confirm the chuck is fully tightened against all three shank flats before operation. Follow applicable OSHA and site safety guidelines for rotating tool use and personal protective equipment.