Value Collection JY4887378 Hand Tap 3/8 Uns Bottoming Hss

Product Description

The VALUE COLLECTION JY4887378 is a straight-flute hand tap designed for cutting 3/8-inch UNS (Unified National Special) internal threads in through-holes and blind holes requiring a bottoming chamfer. Built from high speed steel (HSS) with a bright, uncoated finish, this tap delivers reliable thread-cutting performance in ferrous and non-ferrous materials. The 8-flute design provides increased cutting edge contact, which helps distribute cutting forces and supports consistent thread form. Overall length is 9.75 inches with a 4.5625-inch thread length. Licensed machinists, tool and die makers, and maintenance technicians use this tap for manual threading operations requiring full thread depth to the bottom of a blind hole.

This tap is suited for production and maintenance applications where UNS thread forms are specified. The bottoming chamfer — typically 1 to 2 threads of lead — allows the tap to cut threads close to the bottom of a blind hole, making it appropriate for tooling, fixture, and precision component work. It is driven by a standard tap wrench or T-handle and is compatible with H8 thread limit tolerances, which accommodate medium-fit threading applications.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• H8 thread limit for medium-fit tolerance control
• 8-flute straight flute design distributes cutting load across more edges
• High speed steel construction for durability in a range of workpiece materials
• Bright, uncoated finish — no coating buildup to affect dimensional tolerances
• Right-hand thread direction, standard drive for tap wrenches

Compatibility

Designed for manual hand tapping of 3/8-inch UNS threads with an H8 thread limit. Compatible with standard tap wrench drives used in machine shop, maintenance, and toolroom applications.

Installation Notes

This tap is intended for use by machinists and trained technicians performing manual threading operations. Secure the workpiece firmly before tapping and ensure the pilot hole diameter matches the recommended tap drill size for the specified UNS thread. Apply appropriate cutting fluid to reduce friction and extend tap life. Back the tap off periodically to break chips and prevent binding, particularly in deep or blind holes.