Value Collection JY4849212 Straight Flute Tap 1-20 Unef

Product Description

The VALUE COLLECTION JY4849212 is a straight flute bottoming tap designed for cutting internal threads in blind holes where full thread engagement close to the bottom of the hole is required. Manufactured from high-speed steel with a bright, uncoated finish, this tap is built for durability under normal cutting conditions. It is configured in a 1-20 UNEF thread size with four flutes, a right-hand thread direction, and an H4 thread limit, making it well suited for producing precise, close-tolerance threads in ferrous and non-ferrous materials. The overall length measures 5.125 inches.

This tap is used in machine shops, maintenance facilities, and production environments where fine-pitch unified extra-fine threads are required. The bottoming chamfer — typically two threads of lead — allows threading to within a few threads of a blind hole bottom, which is common in aerospace, hydraulic component, and precision instrument applications. It is appropriate for use in manual tapping operations and compatible with standard tap handles and tapping machines.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• 1-20 UNEF thread specification for fine-pitch unified extra-fine applications
• High-speed steel construction for wear resistance across a wide range of materials
• Four flutes provide balanced chip evacuation and cutting stability
• H4 thread limit for controlled tolerance in 3B class of fit applications
• Right-hand thread direction, bright uncoated finish suitable for use with cutting fluids

Compatibility

Designed as an OEM-style replacement or standard tooling choice for applications requiring a 1-20 UNEF bottoming tap with a 3B class of fit and H4 thread limit.

Installation Notes

This tap should be installed and operated by a qualified machinist or toolroom technician. Secure the workpiece fully before tapping and ensure the tap is aligned perpendicular to the hole to avoid thread distortion or tap breakage. Apply an appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Never apply excessive torque — back the tap off periodically to break and clear chips, especially in deep or blind hole applications.