Product Description
Milwaukee 4-1/4 in. x 12 in. Diamond Core Bit Extension
Model Number: 48-17-4042
The Milwaukee 48-17-4042 is a 4-1/4 in. x 12 in. Diamond Core Bit Extension for use with the Milwaukee 48-17-3042 4-1/4 in. Diamond Premium Wet Core Bit — a 12 in. barrel extension that adds working depth for through-penetrations in thick concrete walls and floors where the standard barrel cannot complete a full penetration from a single drill setup. This extension is specifically engineered as a companion accessory to the Milwaukee 4-1/4 in. Premium Wet Core Bit, and the pairing of the correct extension diameter and the correct core bit is essential — the extension must match the core bit's barrel diameter and connection interface to maintain concentric rotation through the coupling and to allow proper water delivery for cooling and slurry evacuation through the full extended barrel depth. Adding 12 in. of barrel extension to the 4-1/4 in. core bit enables drilling through thick structural concrete sections from a single drill setup without the alignment challenges of two-sided drilling.
Milwaukee precision-machines the extension's connection interface for accurate concentricity between the extension and the core bit — any eccentricity at the coupling introduces runout at the cutting face, producing oversized holes and uneven segment wear that shortens the premium core bit's service life. The extension is used throughout the drilling operation with continuous wet cutting — water delivery must reach the full extended system length for adequate diamond segment cooling and concrete slurry evacuation at the 4-1/4 in. bore's significant cutting interface heat generation. Always follow Milwaukee's recommended feed rate and water application procedures when using barrel extensions to ensure both safe operation and optimal bit and extension service life.
See Milwaukee's complete diamond core bit extension lineup for all available sizes matching other Milwaukee premium wet core bit diameters.
Features
- 12 in. extension for through-penetrations beyond standard 4-1/4 in. core bit barrel depth
- Specifically designed for Milwaukee 4-1/4 in. Diamond Premium Wet Core Bit (48-17-3042)
- Precision-machined coupling for concentric rotation through full extended depth
- Use with continuous wet cutting for segment cooling and slurry evacuation
- Correct extension diameter match is essential — verify bit and extension pairing
Specifications
- Extension Length: 12 in.
- Core Bit Diameter: 4-1/4 in.
- Compatible Bit: Milwaukee 48-17-3042 4-1/4 in. Diamond Premium Wet Core Bit
Includes
- (1) Milwaukee 48-17-4042 4-1/4 in. x 12 in. Diamond Core Bit Extension
