Eagle Cutting Tool C1090-128-I Cobalt Drill Bit 1-7/16 in

Product Description

The EAGLE CUTTING TOOL C1090-128-I is a cobalt slow spiral (screw machine length) drill bit designed for heavy-duty drilling in hard and abrasive materials. Built with a cobalt high-speed steel construction, this bit handles elevated cutting temperatures without losing hardness, making it well suited for production drilling where standard HSS bits wear prematurely. The 1-7/16 inch cutting diameter and 1/2 inch reduced shank allow the bit to seat securely in standard 1/2 inch drill chucks and Jacobs-style keyless chucks without requiring a larger machine spindle.

This drill bit is used in metalworking, fabrication, and maintenance applications where large-diameter holes are needed in stainless steel, hardened steel, cast iron, titanium, and other tough alloys. The slow spiral geometry reduces chip packing and improves rigidity in shorter-length drilling operations. It is typically run on drill presses, milling machines, or heavy-duty electric drills in commercial and industrial shop environments. Machinists, tool-and-die workers, pipefitters, and industrial maintenance technicians commonly use this size for pipe flanges, structural steel, and manifold work.

Key Features

• Cobalt high-speed steel construction resists heat buildup during high-speed or dry cutting
• Slow spiral geometry reduces chip load and improves hole quality in short-length drilling
• 1-7/16 inch cutting diameter suits large-bore hole requirements in metal fabrication
• 1/2 inch reduced shank fits standard 1/2 inch chucks without requiring a larger spindle bore
• Screw machine length profile provides added rigidity compared to jobber-length bits of the same diameter

Compatibility

Designed as an OEM-style replacement or direct-use cobalt drill bit for any drill press, milling machine, or heavy-duty hand drill equipped with a 1/2 inch or larger chuck accepting a 1/2 inch reduced shank.

Installation Notes

Installation is performed by machinists or qualified tradespeople familiar with machine tool operation. Secure the shank fully into the chuck and confirm runout before beginning a cut. Always set spindle speed appropriate for the workpiece material and bit diameter — larger diameter bits require lower RPM. Use cutting fluid or coolant when drilling ferrous metals to extend bit life and maintain dimensional accuracy.

Technical Specifications

• Cutting Diameter: 1-7/16 inches
• Shank Diameter: 1/2 inch
• Bit Material: Cobalt High-Speed Steel
• Spiral Type: Slow Spiral (Screw Machine Length)
• Weight: 1.2 pounds
• Minimum Order Quantity: 1

Standard Information

• Brand: EAGLE CUTTING TOOL
• Manufacturer Part Number: C1090-128-I