Drill bit set Proline 78048K — metal bits Ø4.8 mm, length 86 mm, 2 pcs

Proline 78048K is a set of two metal drill bits with a 4.8 mm diameter and an 86 mm working length. Manufactured from high-speed steel with 5% cobalt (HSS-Co), these straight shank bits are intended for drilling demanding metals, including high-alloy steels, stainless and acid-resistant steels, titanium, and cast iron. The bits are fully ground for precise geometry and straightness, and feature a 135° point angle with chamfering adjustment to enable fast, accurate starts and reduced need for repositioning during marking.

Advantages

The HSS-Co material ensures elevated heat resistance and prolonged cutting life when working at higher temperatures. Full grinding production guarantees high dimensional accuracy and rectilinearity of holes. The 135° point angle with chamfering adjustment improves centering and reduces walking on the work surface, allowing quicker penetration and consistent hole quality. Supplied in a compact blister pack, the set provides two identical bits suitable for both hand drills and drill presses.

Suitable for

• Drilling through high-alloy and stainless steels
• Creating precise 4.8 mm holes in metal fabrication and repair
• Use in maintenance, installation, and assembly tasks
• Drilling tougher materials such as titanium and cast iron

Key specifications

• Diameter: 4.8 mm
• Working length: 86 mm
• Shank type: straight shank
• Material: high-speed steel with 5% cobalt (HSS-Co)
• Point angle: 135° with chamfering adjustment
• Manufacturing: fully ground flutes for high accuracy
• Pack content: 2 identical pieces

How to use

Secure the drill bit in the chuck of a hand drill or drill press, ensuring concentric clamping to avoid runout. Mark the drilling position and, if necessary, use a center punch to prevent the bit from wandering. Start drilling at moderate speed and apply steady, even pressure; for harder materials and to extend tool life, use lower speeds and periodic pecking to clear chips and reduce heat buildup. Use appropriate cutting fluid for stainless and heat-resistant steels to improve performance and tool life.

Usage recommendations

For best results when drilling high-alloy or stainless steels, use cutting lubricant, maintain lower spindle speeds, and withdraw the bit periodically to clear chips. When drilling thin sheets, consider backing the workpiece to prevent burrs or deformation. Store the bits in their blister pack to protect the ground cutting edges.