Cleveland C57047 Spiral Point Tap 4-40 Unc Hss

Product Description

The CLEVELAND C57047 is a spiral point plug tap designed for through-hole threading in a wide range of ferrous and non-ferrous materials. Built from high speed steel (HSS) with a bright finish, it drives chips forward ahead of the cutting edges, keeping flutes clear during the threading pass. The tap is ground to an H1 thread limit and cut to a Class 2B fit, making it suitable for standard-tolerance tapped holes in production and maintenance applications. With a 4-40 UNC thread form, 2 flutes, and a plug chamfer, it is a go-to choice for machinists, maintenance technicians, and tool-and-die tradespeople working in light-gauge metal assemblies.

This tap is used for through-hole threading operations on alloy steel, carbon steel, and aluminum workpieces. The plug chamfer provides a gradual lead-in over several threads, making it appropriate for starting and completing a through-hole in one pass. At 1.875 inches overall length with a 0.3100-inch thread length and a 0.141-inch shank diameter, the C57047 fits standard tap handles and machine tool collets sized for small-diameter taps. Typical applications include instrument assembly, electrical panel fabrication, and general-purpose machine shop work where 4-40 fasteners are specified.

Key Features

• Spiral point geometry pushes chips forward during through-hole threading, reducing clogging and breakage risk
• High speed steel construction provides durability across alloy steel, carbon steel, and aluminum applications
• Plug chamfer allows gradual thread engagement, suitable for through-hole starts without a bottoming tap
• H1 thread limit ground to Class 2B fit for standard-tolerance threaded holes
• Bright finish — no coating buildup — maintains dimensional consistency close to ground geometry
• Right-hand cut, 40 threads per inch, UNC standard thread form

Compatibility

Designed for through-hole threading in alloy steel, aluminum, and carbon steel. Compatible with standard tap handles and machine collets accepting a 0.141-inch (3.58 mm) shank diameter. Series 1011.

Installation Notes

Machinists and maintenance technicians should drill the correct tap drill size for 4-40 UNC before threading. Ensure the workpiece is securely fixtured before engaging the tap to prevent thread damage or tool breakage. Apply appropriate cutting fluid for the workpiece material — aluminum and steel each benefit from different lubricants. For machine tapping, confirm spindle speed is appropriate for HSS tooling in the material being cut; excessive speed accelerates tool wear and increases breakage risk in small-diameter taps.