Drill bit Proline 5.1 mm (length 86 mm) model 77851K — 1 pc

Single metal drill bit Proline 77851K with a 5.1 mm diameter and 86 mm overall length. This solid twist drill is engineered for drilling steel and other metals; its full-length precision grinding and titanium nitride coating improve wear resistance and hole finish. The 135° point angle with chamfering support enables fast centring and reduced walking during marking and starts, making it suitable for general metalworking, repairs and installation tasks where a medium-diameter metal drill is required.

Advantages

The drill is manufactured entirely by grinding to ensure concentricity and cutting geometry accuracy. A titanium nitride surface coating increases tool life and reduces friction for smoother penetration and improved hole quality. The 135° point angle with chamfer adjustment helps achieve quick, accurate starts and reduces the need for pilot holes in many metal applications. Supplied as a single piece in a blister pack that protects the cutting edge during storage and transport.

Suitable for

• Drilling holes in steel, cast iron and non-ferrous metals
• General metal fabrication and workshop repairs
• Assembly and installation where precise medium-diameter holes are required
• Maintenance tasks and retrofit drilling in mechanical components

Key specifications

• Drill type: solid twist drill for metal
• Diameter: 5.1 mm
• Overall length: 86 mm
• Point angle: 135° with chamfering adjustment
• Manufacturing: full-length precision grinding
• Coating: titanium nitride (TiN) for increased wear resistance
• Packaging: single piece in a protective blister pack

How to use

Secure the workpiece and select an appropriate clamp or vise to prevent movement. Mark the hole position and, if needed for thin or hard materials, use a centre punch to create a starting dimple. Fit the 5.1 mm drill bit into the drill chuck and tighten securely. Use a steady feed and moderate speed appropriate to the metal type; apply cutting fluid or lubricant for improved cooling and chip evacuation. Withdraw the bit periodically to clear chips and prevent clogging. After drilling, deburr the hole as required.

Usage recommendations

For best performance, use recommended cutting speeds for the specific metal being drilled and apply cutting fluid when working with steel or alloyed materials. Start with a pilot hole if drilling in very hard or thick sections, and ensure the drill chuck is properly tightened to avoid runout.