Cleveland C54471 Hand Tap 1/4-28 Unf Bottoming Hss

Product Description

The CLEVELAND C54471 is a 1/4-28 UNF bottoming hand tap machined from high speed steel with a bright uncoated finish. It features a 4-flute straight flute geometry and a right-hand thread direction, designed for cutting internal threads in both blind holes and through-holes. With an overall length of 2.5 inches and a thread length of 0.63 inches, this Series 1003 tap is built to produce Class 3B threads at an H3 thread limit. Machinists and toolroom technicians reach for this tap when a bottoming chamfer is needed to thread close to the bottom of a blind hole where standard or plug taps cannot reach.

This tap is suited for general-purpose threading operations in job shop, maintenance, and production environments. The bottoming chamfer style makes it especially useful as a finishing tap following a plug tap in blind hole applications. It handles a range of common workpiece materials including alloy steel, carbon steel, aluminum, and free-machining stainless steel. The 1/4-28 UNF thread form is common in precision mechanical assemblies, hydraulic fittings, and instrumentation hardware where a fine thread pitch is required for improved holding strength or adjustment sensitivity.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• 4-flute straight flute design for accurate thread form and chip control
• High speed steel construction for durability across multiple workpiece materials
• Bright uncoated finish — no coating buildup that could affect thread tolerance
• H3 thread limit produces Class 3B fit for standard precision thread assemblies
• Right-hand cut, compatible with standard tapping handles and tap wrenches

Compatibility

Designed for use in alloy steel, aluminum, carbon steel, and free-machining stainless steel workpieces. Suitable for both blind hole threading and through-hole threading applications requiring a 1/4-28 UNF Class 3B thread form.

Installation Notes

This tap is installed by machinists or maintenance technicians using a standard tap wrench or tapping handle sized for the 0.191-inch square drive. Secure the workpiece before tapping and use an appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. In blind hole applications, use a plug tap first to establish the thread, then follow with this bottoming tap to thread closer to the hole bottom. Do not force the tap — back off regularly to break chips and prevent tap breakage.