Drill bit Proline 78125K — metal drill bit Ø12.5 mm, length 151 mm, 1 pc

Proline 78125K is a single HSS-Co metal drill bit with a 12.5 mm diameter and an overall length of 151 mm, intended for precise through-holes and fitting tasks in metalworking. The solid, fully ground flute geometry ensures straight, accurate holes while the 135° point angle with chamfering adjustment promotes fast centre penetration and reduced walking on the workpiece. Manufactured from high-class high-speed steel with 5% cobalt, this drill bit offers increased red-hardness and resistance to heat for demanding metal drilling applications.

Advantages

The combination of HSS with 5% cobalt improves durability when cutting high-alloy and stainless steels and cast iron; fully ground construction guarantees rectilinearity and dimensional accuracy; the 135° point with chamfering adjustment enables quick drilling and easier marking alignment; higher temperature resistance maintains cutting performance during extended operation.

Suitable for

• Drilling holes in high-alloy and stainless steels
• Work on titanium and acid-resistant metals
• Maintenance and workshop repair tasks requiring precise Ø12.5 mm holes
• Construction jobs where durable metal drilling is needed

Key specifications

• Material: high-speed steel with 5% cobalt (HSS-Co)
• Diameter: 12.5 mm
• Overall length: 151 mm
• Point angle: 135° with chamfering adjustment
• Manufacturing: fully ground flutes for high accuracy and straightness
• Suitability: high temperature and wear resistance for hard-to-machine metals
• Packaging: sold as a single piece in blister pack

How to use

Secure the workpiece and use an appropriate drill press or hand drill with sufficient rigidity for a 12.5 mm diameter bit. Clamp the drill bit firmly in the chuck to minimize runout. For best results, use a centre punch or the chamfering adjustment to mark the drilling point before starting. Start at low speed to establish the hole, then apply steady feed and increase speed within the drill’s recommended range for metal cutting. Use cutting fluid or coolant when drilling stainless, titanium or other heat-sensitive alloys to reduce friction and extend tool life. Clear chips frequently to avoid clogging the flutes.

Usage recommendations

The drill bit is intended for professional and workshop use on hard and high-alloy metals; to extend service life, use appropriate cutting speeds, steady feed rates, and coolant. Avoid excessive axial force and overheating; re-sharpen only using proper grinding techniques to preserve the 135° point geometry.