Cleveland C54457 Hand Tap 1/4-20 Bottoming Hss Unc

Product Description

The CLEVELAND C54457 is a 1/4-20 bottoming hand tap designed for cutting internal threads in both blind holes and through-holes. Made from high speed steel with a bright uncoated finish, it delivers consistent thread cutting performance across a range of common workpiece materials. The two-flute straight flute geometry provides chip clearance and cutting stability suited to hand tapping operations. With a class of fit of 3B and a thread limit of H3, this tap produces standard-tolerance UNC internal threads. The overall length is 2.5 inches, with a thread length of 0.63 inches, making it appropriate for controlled-depth bottoming applications where full thread depth near the bottom of a blind hole is required.

This tap is used in machine shops, maintenance and repair operations, and fabrication environments where 1/4-20 UNC internal threads need to be cut or re-chased. The bottoming chamfer style is chosen when threading must extend as close to the bottom of a blind hole as possible, typically after a taper or plug tap has started the thread. It is driven by a standard tap wrench or T-handle and is suited for hand tapping operations in alloy steel, aluminum, carbon steel, and free-machining stainless steel workpieces. Series 1003.

Key Features

• Bottoming chamfer geometry threads to the bottom of blind holes
• High speed steel construction handles a broad range of metal workpiece materials
• Bright uncoated finish suitable for general-purpose tapping applications
• 2-flute straight flute design provides chip clearance during hand tapping
• 3B class of fit and H3 thread limit produce standard UNC tolerance internal threads
• Right-hand thread direction, compatible with standard tap wrenches and T-handles

Compatibility

Designed for cutting 1/4-20 UNC internal threads in alloy steel, aluminum, carbon steel, and free-machining stainless steel. Suitable for both blind hole and through-hole threading applications.

Installation Notes

Use an appropriate tap wrench or T-handle sized for the 0.255-inch shank diameter. Ensure the workpiece hole is drilled to the correct tap drill size for 1/4-20 UNC threads before tapping. Apply cutting fluid appropriate to the workpiece material to extend tool life and improve thread quality. When tapping blind holes, use a taper or plug tap first to start the thread, then follow with this bottoming tap to complete the thread depth.