Drill bit Proline 77655, metal bit, Ø 5.5 mm, length 260 mm, 1 pc

Proline 77655 is a single HSS metal drill bit with a 5.5 mm diameter and a total length of 260 mm, designed for use in handheld drills and drill presses. The extra-long, fully ground body provides rectilinear drilling and is suitable for through-holes and accurate pilot holes in steel, non-ferrous metals and plastics. The 135° point angle with chamfering adjustment enables fast penetration and reduces the need for extensive marking out before drilling. Supplied as one piece, it is intended for general metalworking and maintenance tasks that require a medium-sized drilling diameter.

Advantages

The drill is made from high-quality refined high-speed steel (HSS), offering good hardness and wear resistance for repeated metal drilling operations. Fully ground flutes ensure high positional accuracy and straightness of holes, which is beneficial when working with drill bushes or when precise alignment is required. The 135° point geometry with chamfering reduces walking and improves centering, while the extra length allows access to deeper holes or recessed workpieces without extensions.

Suitable for

• Drilling through-holes and pilot holes in steel and non-ferrous metals
• Working with plastics where a long reach is needed
• Use in handheld drills and drill presses for general maintenance and fabrication

Key specifications

• Diameter: 5.5 mm
• Overall length: 260 mm
• Point angle: 135° with chamfering adjustment
• Material: refined high-speed steel (HSS)
• Design: fully ground, extra-long flute geometry for straight drilling
• Pack: single piece

How to use

Clamp the workpiece securely and select an appropriate drill speed for the material—moderate speeds for steel, higher for non-ferrous metals and plastics. Mark the drilling point or use a center punch to prevent walking, then align the drill bit perpendicular to the surface. Apply steady, controlled feed pressure and allow the bit to cut without forcing; withdraw periodically to clear chips when drilling deep holes. For handheld use, maintain stable grip and ensure the drill is held square to the workpiece.

Usage recommendations

Use cutting fluid or lubricant when drilling steels to extend bit life and improve hole finish. For non-ferrous metals and plastics, a suitable lubricant or reduced speed can help prevent material buildup on the flutes. Replace the bit if accuracy or cutting performance degrades; regrinding is possible if the geometry is preserved.