Drill bit set Proline Tools 78008K — 5 pieces, 0.8 mm diameter, 30 mm length

Proline Tools 78008K — 5 pieces, 0.8 mm diameter, 30 mm length is a set of five high-speed steel (HSS) cobalt drill bits designed for precision metalworking. Each bit has a 0.8 mm working diameter and a 30 mm overall length, ground for accuracy and straightness. The drills feature a 135° point angle with chamfering adjustment to facilitate rapid centering and reduce time spent on marking out. Made from HSS with 5% cobalt, these bits resist high temperatures and are intended for demanding materials including high-alloy, titanium, acid-resistant and stainless steels, creep-resisting steels, cast iron and other hard-to-machine metals.

Advantages

The drills are produced entirely by grinding, ensuring high dimensional accuracy and rectilinearity of holes. A 135° point angle combined with chamfering adjustment improves centering and chip evacuation for small-diameter work. Construction from highest-class HSS with 5% cobalt increases resistance to heat and wear, extending tool life when drilling hard alloys and stainless materials. The blister pack keeps the five bits organized and protected for storage and transport.

Suitable for

• Precision model making and miniatures
• Electronics and PCB drilling for component leads and vias
• Fine mechanical work and watchmaking repairs
• Handheld and benchtop drilling where small, accurate holes are required

Key specifications

• Quantity: 5 drill bits
• Diameter: 0.8 mm
• Overall length: 30 mm
• Material: high-speed steel (HSS) with 5% cobalt
• Point angle: 135° with chamfering adjustment
• Manufacturing method: fully ground flutes and tips for accuracy
• Suitable materials: high-alloy steels, titanium, acid-resistant and stainless steels, creep-resisting steels, cast iron and other hard-to-machine metals

How to use

Select an appropriate drill speed and feed for a 0.8 mm diameter HSS cobalt drill bit and secure the workpiece in a vice or jig to prevent movement. Use a center punch or pilot mark where possible to aid accurate positioning; the 135° point improves self-centering but a faint punch mark can reduce walking. Apply cutting fluid when drilling stainless, high-alloy or heat-sensitive materials to improve lubrication and reduce heat build-up. Start drilling at a low speed to establish the hole, then increase speed cautiously while maintaining steady, light feed pressure. Periodically withdraw the bit to clear chips and reapply cutting fluid as needed. After drilling, deburr the hole edges with a small file or deburring tool.

Usage recommendations

For best results when working with stainless and high-alloy steels, use moderate spindle speeds, constant lubrication, and light, consistent feed to minimize bit overheating and wear. Store bits in their blister pack to protect ground tips from damage.