Milwaukee 48-20-4078 Spline Drill Bit 3/4 in 22 in

Product Description

The MILWAUKEE 48-20-4078 is a spline-shank rotary hammer drill bit engineered for high-torque drilling in concrete and masonry. The spline drive shank features 12 grooves that mesh with matching grooves in spline-drive rotary hammer chucks, locking the bit securely during aggressive drilling and preventing slippage under load. At 3/4 inch in diameter with a 22-inch overall length and a maximum drilling depth of 17 inches, this bit handles deep-penetration work in thick concrete slabs, block walls, and similar hard substrates. The carbide cutting heads deliver durability in abrasive materials.

This bit is designed for professional use in residential and commercial concrete and masonry applications. Typical install scenarios include anchor hole drilling in concrete foundations, through-drilling in block and brick walls, and structural tie-in work requiring consistent hole diameter and depth. The 22-inch overall length provides reach for deep structural assemblies. Licensed contractors, concrete trades, and electricians performing anchor work rely on bits of this type for repeatable results in demanding field conditions.

Key Features

• Spline drive shank with 12-groove engagement prevents bit slippage during high-torque rotary hammer drilling
• 3/4-inch diameter with 17-inch maximum drilling depth for deep anchor and through-hole applications
• Carbide cutting material rated for concrete and masonry substrates
• Impact rated construction withstands repeated hammer action in rotary hammer drills
• Bright uncoated finish on machined surfaces
• 22-inch overall length provides reach for deep structural drilling applications

Compatibility

Designed for use with rotary hammer drills equipped with spline-drive chucks. Not compatible with SDS-Plus or SDS-Max chuck systems.

Installation Notes

Installation and removal require a spline-drive rotary hammer drill. Before changing bits, power down and disconnect the tool from its power source per standard lockout procedure. Wear appropriate eye and respiratory protection when drilling concrete or masonry. Inspect the bit shank for wear or damage before each use and replace if grooves show deformation that could affect chuck engagement.