Value Collection JY4849188 Hand Tap 1-18 Uns Bottoming Hss

Product Description

The VALUE COLLECTION JY4849188 is a bottoming hand tap designed for cutting internal threads in pre-drilled holes where full thread engagement is required close to the bottom of a blind hole. Manufactured from high speed steel with a bright, uncoated finish, this tap handles right-hand threading in a 1-18 UNS thread form. It features four straight flutes for efficient chip evacuation and carries a Class 3B fit with an H4 thread limit, making it suitable for applications requiring close-tolerance internal threads. Overall length is 5.125 inches. Machinists, tool-and-die workers, and maintenance technicians use this tap in manual tapping operations with a standard tap wrench.

This tap is suited for threading metallic workpieces in job shop, production, and maintenance-repair-overhaul environments. Its bottoming chamfer — typically 1 to 2 threads of lead — allows threading to within a few threads of the bottom of a blind hole, which is essential when mating fasteners must seat fully in shallow or stopped bores. The UNS thread form covers non-standard pitch combinations not addressed by standard UNC or UNF series, so this tap is particularly useful for specialty or legacy hardware applications. Coolant-through capability is not included; external cutting fluid application is standard practice for manual hand tapping.

Key Features

• Bottoming chamfer for threading close to the bottom of blind holes
• High speed steel construction for durability across ferrous and non-ferrous materials
• Bright, uncoated finish — suitable for use with a wide range of cutting fluids
• Four straight flutes for effective chip clearance in through and blind hole applications
• Class 3B fit with H4 thread limit for close-tolerance internal threading
• Right-hand thread direction for standard tapping operations

Compatibility

Designed as an OEM-style replacement or standard hand tap for manual tapping operations requiring a 1-18 UNS right-hand bottoming tap with a 3B Class of Fit.

Installation Notes

Hand tapping should be performed by a qualified machinist or maintenance technician using an appropriately sized tap wrench. Ensure the workpiece is securely fixtured and the pilot hole diameter is correct for the 1-18 UNS thread before starting. Apply cutting fluid to the tap and workpiece before and during tapping to reduce heat and extend tool life. Back the tap off periodically to break chips and prevent tap breakage, especially in deeper or harder materials.