Drill bits set Proline 78035K — metal bits, 3.5 mm diameter, 70 mm length, 3 pcs

Proline 78035K drill bits set contains three high-speed steel metal bits with 3.5 mm working diameter and 70 mm overall length, intended for drilling accurate holes in metal and other solid materials. The bits have a 135° point angle with chamfering adjustment to facilitate fast centring and reduce walking on start, and are produced by grinding to ensure straightness and dimensional accuracy. Manufactured from premium HSS with 5% cobalt, these bits offer elevated temperature resistance and durability when working with high-alloy steels, titanium, stainless and acid-resistant steels, creep-resisting steels, cast iron and other difficult-to-machine materials.

Advantages

These drill bits combine a 135° split-point geometry with precise grinding to deliver fast penetration, reduced skidding at the start and consistently straight holes. The use of HSS with 5% cobalt increases hardness at elevated temperatures and extends service life when drilling hard and heat-resistant alloys. The straight shank design makes the bits compatible with hand drills, drill drivers and drill chucks used in workshop, maintenance and light fabrication tasks. The blister packaging keeps the set organized and protects the bits during storage and transport.

Suitable for

• Drilling holes in stainless steel and acid-resistant steels
• Working with high-alloy and creep-resisting steels
• Fabrication, maintenance and workshop repair tasks
• Drilling into cast iron and other hard materials
• Use with hand drills, drill drivers and bench drills

Key specifications

• Diameter: 3.5 mm (working diameter)
• Overall length: 70 mm
• Material: high-speed steel (HSS) with 5% cobalt
• Point angle: 135° with chamfering adjustment (split-point geometry)
• Manufacturing: fully ground flutes for high straightness and accuracy
• Shank type: straight shank suitable for standard chucks
• Pack quantity: 3 pieces

How to use

Secure the correct bit in the drill chuck and tighten firmly. Mark the drilling position and, if needed, create a small centre punch dimple to prevent wandering. Start drilling at a low speed to allow the 135° point to engage, then increase speed appropriate to the material while applying steady, moderate pressure. Use cutting fluid or lubricant when drilling stainless steel, high-alloy steels or other heat-sensitive materials to reduce friction and prolong bit life. After use, clean chips from the flutes and store the bits in their blister pack to avoid damage.

Usage recommendations

To maximise tool life and hole quality, use lower speeds and light feeds for hard and heat-resistant materials, maintain proper lubrication, and avoid excessive pressure that may cause overheating or premature wear. Replace bits that show significant wear, chipping or loss of geometry.