Cleveland C57049 Spiral Point Tap 4-40 Unc Bottoming Hss

Product Description

The CLEVELAND C57049 is a spiral point tap designed for cutting internal threads in blind holes using the bottoming chamfer style. Built from high speed steel with a bright finish, this tap handles 4-40 UNC threads with a right-hand cutting direction and an H2 thread limit for close-tolerance work. It features 2 flutes and a thread length of 0.31 inches, with an overall length of 1.875 inches. The bottoming chamfer allows threading closer to the bottom of a blind hole than plug or taper styles. Licensed machinists, tool and die makers, and HVAC or electrical trade technicians performing tapping operations on equipment enclosures and brackets are the primary installers.

This tap is suited for threading blind holes in softer to medium-hardness materials including aluminum, copper alloys, low carbon steel, and magnesium. The 4-40 UNC thread size is common in small fastener applications found in electrical panels, instrumentation enclosures, and light mechanical assemblies. The 2B/3B class of fit covers both commercial and precision threading applications, making this tap versatile across general production and maintenance work.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• High speed steel construction for durability across aluminum, copper alloys, low carbon steel, and magnesium
• H2 thread limit for controlled tolerance threading
• 2B/3B class of fit supports both commercial and precision applications
• Bright finish with no coolant-through requirement, suitable for standard tapping with cutting fluid applied externally
• Right-hand cutting direction, standard for 4-40 UNC fastener systems

Compatibility

Designed for blind hole threading in materials including aluminum, copper alloys, low carbon steel, and magnesium. Fits standard tap holders and tapping chucks accepting a 0.141-inch shank diameter.

Installation Notes

Tapping operations should be performed by qualified machinists or trade technicians familiar with proper speeds, feeds, and cutting fluid application for the material being tapped. Always secure the workpiece firmly before beginning threading. Use a proper tap wrench or machine tapping setup to maintain axial alignment and prevent tap breakage. Back the tap out periodically to clear chips when threading blind holes.