Cleveland C57154 Spiral Point Tap 5/16-18 Unc Hss

Product Description

The CLEVELAND C57154 is a spiral point plug tap designed for through-hole threading in a range of ferrous and non-ferrous metals. Built from high speed steel (HSS) with a bright finish, it cuts a 5/16-18 UNC thread to a Class 2B fit tolerance. The spiral point geometry pushes chips forward ahead of the cutting zone, making it well-suited for threading blind-ended through holes at production volumes. With an H5 thread limit and 2 flutes, it delivers consistent thread quality in both hand and machine tapping operations. Licensed trades and machining professionals rely on this style of tap for general-purpose threading work on structural and fabricated assemblies.

This tap is used in through-hole threading applications on alloy steel, carbon steel, and aluminum workpieces. It is appropriate for both manual tapping with a tap wrench and powered tapping on drill presses, CNC machining centers, and tapping machines. The plug chamfer (approximately 3 to 5 threads of taper) makes it a standard starting tap where the tool enters a pre-drilled hole and threads the full depth. It is commonly specified in fabrication shops, maintenance and repair operations, and production manufacturing environments.

Key Features

• Spiral point geometry pushes chips forward, ideal for through-hole threading
• High speed steel construction provides wear resistance across steel and aluminum substrates
• 5/16-18 UNC thread form, Class 2B fit, H5 thread limit for consistent tolerance control
• Plug chamfer for standard entry into pre-drilled through holes
• Bright finish — no coating buildup that could affect thread tolerance in tight-limit applications
• Right-hand cut, compatible with standard tapping heads and tap wrenches

Compatibility

Designed for through-hole threading in alloy steel, carbon steel, and aluminum. Compatible with standard 5/16-18 UNC pre-drilled hole sizes per ASME B1.1 specifications.

Installation Notes

A licensed machinist or maintenance technician should confirm proper drill size for the specified thread class before tapping. Secure the workpiece fully before operation and use appropriate cutting fluid for the material being tapped. When using in a powered tapping setup, verify that the tapping head or CNC program is set for the correct feed rate matching the 18 threads per inch pitch. Reverse the tap periodically in hand operations to break chips and prevent binding.