Milwaukee 48-89-2517 Cobalt Jobber Drill Bit 4.3 in

Product Description

The MILWAUKEE 48-89-2517 is a cobalt jobber-length twist drill bit built for drilling in hard metals where standard high-speed steel bits fail prematurely. It features a variable helix geometry that transitions from an aggressive 35-degree angle down to 15 degrees, promoting rapid chip evacuation and reducing heat buildup at the cutting edge. The 135-degree split point tip starts on contact without center-punching and prevents the bit from walking on smooth or curved surfaces. This bit is sold individually and is sized to metric specifications. Licensed tradespeople and machinists working in fabrication, mechanical, or industrial maintenance applications reach for this bit when drilling stainless, hardened steel, and other tough alloys.

The 48-89-2517 is suited for hard-metal drilling tasks in both shop and field environments. Typical applications include drilling through structural steel, stainless steel fastener clearance holes, and other ferrous metals that generate high cutting temperatures. The cobalt alloy construction maintains hardness at elevated temperatures, making it effective for sustained, high-cycle use in production or service settings. It fits standard keyed and keyless chucks and is compatible with corded and cordless drill drivers running appropriate speeds for the material being drilled.

Key Features

• Cobalt alloy construction maintains hardness under high heat for extended bit life in hard metals
• Variable helix design transitions from 35 degrees to 15 degrees for rapid chip removal and reduced heat buildup
• 135-degree split point tip starts on contact and prevents walking without center-punching
• Chip breaker geometry further limits heat accumulation during drilling
• Secure grip shank design reduces slipping in the chuck during high-torque operation
• Metric sizing for precision clearance and tap-drill applications

Compatibility

Designed as a jobber-length cobalt twist drill bit compatible with standard keyed and keyless drill chucks across corded and cordless drilling platforms.

Installation Notes

This bit is installed by a machinist, fabricator, or journeyman tradesperson familiar with metal-cutting speeds and feeds appropriate to the base material. Set drill speed according to the material hardness and bit diameter before beginning — cobalt bits require lower RPM in hard metals compared to softer stock. Secure the workpiece firmly before drilling to prevent movement. Applying cutting fluid or oil during drilling extends bit life and reduces thermal stress on the cutting edge.