Osg HP255-1378 Solid Carbide Jobber Drill Bit 3.5 Mm

Product Description

The OSG HP255-1378 is a solid carbide jobber-length drill bit designed for high-performance drilling in ferrous materials. It measures 3.5 mm in diameter with an overall length of 66 mm and a flute length of 28 mm. The 140-degree point angle with R-thinned web geometry reduces thrust and improves self-centering at entry. A WD1 coating adds wear resistance and helps manage heat buildup during extended drilling cycles. The straight-cylindrical shank measures 6 mm in diameter, fitting standard drill chucks and collet holders. Right-hand spiral flutes evacuate chips efficiently in both through-hole and blind-hole applications. This bit is suited for machinists, tool-and-die shops, and maintenance technicians working with steel, alloy steel, and cast iron.

The HP255-1378 is built for demanding production and job-shop environments where hole quality and tool life in hard ferrous materials are priorities. Rated for steel and alloy steel under primary workpiece material codes P and K, it handles blind hole, cross hole, standard drilling, and self-centering operations. The 5xD flute-to-diameter ratio provides adequate chip clearance for moderate-depth holes without the need for peck cycles in most applications. The tapered web configuration adds rigidity at the cutting tip, making this bit effective on CNC machining centers, drill presses, and hand-held power tools where a collet or chuck can secure a 6 mm shank.

Key Features

• Solid carbide construction for rigidity and wear resistance in ferrous materials
• WD1 coating reduces friction and extends tool life in steel and alloy steel
• 140-degree R-thinned point improves self-centering and reduces entry thrust
• Coolant-through design supports internal coolant delivery to the cutting edge
• Straight-cylindrical 6 mm shank fits standard collets and drill chucks
• Right-hand spiral flutes with regular spiral type for consistent chip evacuation

Compatibility

Designed for use in steel, alloy steel, and cast iron workpieces. Suitable for blind hole, cross hole, drilling, and self-centering tool applications. Part of the OSG Series HP255 high-performance carbide drill line covering the 3.00 mm to 4.00 mm diameter range.

Installation Notes

Secure the 6 mm straight-cylindrical shank in a properly sized collet or drill chuck before use. Ensure the machine spindle is fully stopped and the workpiece is firmly fixtured before bit engagement. When using the coolant-through feature, confirm that the machine tool's internal coolant system is compatible with the shank diameter and that coolant pressure is set per the machine manufacturer's guidelines. Inspect the cutting edge for wear or chipping before each use, as carbide tooling can fail suddenly under interrupted cuts if the edge is compromised.