Value Collection MSC-04489415 Bottoming Tap 1-1/4-7 Unc Hss

Product Description

The VALUE COLLECTION MSC-04489415 is a straight flute bottoming tap designed for cutting internal threads in through-holes and blind holes where threads must extend close to the bottom. Ground from high-speed steel with a bright, uncoated finish, this tap handles 1-1/4-7 UNC right-hand threads with a 3B class of fit and an H4 thread limit. It carries four flutes and a bottoming chamfer, making it the final-pass tool in a standard tap sequence when full thread depth at the base of a blind hole is required. Overall length is 5.75 inches with a thread length of 2.5625 inches.

This tap is suited for machine shop, maintenance, and fabrication environments where 1-1/4-7 UNC internal threads are produced in ferrous and non-ferrous materials. Typical applications include tapping blind holes in structural components, machinery housings, and heavy equipment fixtures. The bottoming chamfer — typically 1 to 2 threads of lead — is used after a taper or plug tap has already started the thread, allowing thread engagement as close to the bottom of the hole as possible. Machinists and tool-and-die technicians working in manual or CNC tapping operations will find this tap appropriate for production and repair work alike.

Key Features

• Bottoming chamfer provides 1 to 2 threads of lead for maximum thread depth in blind holes
• High-speed steel construction offers toughness and wear resistance across a broad range of workpiece materials
• Bright, uncoated finish allows visual inspection of the cutting edges and suits general-purpose applications
• H4 thread limit maintains consistent tolerance control for 3B class of fit requirements
• Four straight flutes provide chip clearance and stability during the tapping operation
• Right-hand thread direction compatible with standard tapping equipment and tap holders

Compatibility

Designed as an OEM-style replacement or standard tooling option for any application requiring a 1-1/4-7 UNC bottoming tap with a 3B class of fit; compatible with standard tap holders and tapping heads sized for large-diameter straight-shank taps.

Installation Notes

This tap should be used as the final step in a three-tap sequence — taper, plug, then bottoming — to avoid overloading the bottoming tap on unprepared material. Secure the workpiece and ensure the tap is properly aligned with the drilled hole before engaging to prevent tap breakage or thread distortion. Apply appropriate cutting fluid for the workpiece material to extend tap life and improve thread finish. Always power down tapping equipment before changing or inspecting taps.