Value Collection JY9975525 Extension Tap 1/4-20 Unc Hss

Product Description

The VALUE COLLECTION JY9975525 is a spiral point plug extension tap designed for cutting internal UNC threads in through-hole applications. Built from high-speed steel, this tap handles the threading demands of general machining, maintenance, and repair work across metal fabrication and industrial service environments. The 1/4-20 UNC thread size and H3 thread limit ensure consistent dimensional accuracy for standard fastener fits. At 6 inches overall length, the extended reach makes this tap suitable for threading recessed or deep-access bores where a standard-length tap cannot reach. Two flutes provide efficient chip evacuation during the cutting process.

This extension tap is suited for production machining, tool room work, and maintenance applications where 1/4-20 UNC threads are required in locations with limited access or extended reach requirements. The plug chamfer style, with approximately 3 to 5 chamfered threads at the lead, makes it appropriate for through-holes and is the most common general-purpose chamfer style. A Class 3B fit designation means the resulting threads meet tight tolerance standards suitable for precision assemblies and standard 1/4-20 fastener engagement.

Key Features

• 1/4-20 UNC thread form with H3 thread limit for controlled tolerance output
• Spiral point design pushes chips ahead of the tap, reducing clogging in through-hole threading
• Plug chamfer with approximately 3 to 5 lead threads for general-purpose through-hole use
• High-speed steel construction provides wear resistance across a range of workpiece materials
• 6 inch overall length allows threading in deep-set or hard-to-reach bore locations
• Class 3B fit produces tight, precise threads for standard fastener assemblies

Compatibility

Designed for use in through-hole applications requiring 1/4-20 UNC internal threads with a Class 3B fit. Compatible with standard tap holders and extension tap adapters sized for 1/4-inch tap shanks.

Installation Notes

This tap is installed by a machinist or maintenance technician using a standard tap wrench, tapping head, or CNC tapping attachment. Ensure the workpiece is securely fixtured and the pilot hole is drilled to the correct tap drill diameter for 1/4-20 UNC threads before beginning. Apply appropriate cutting fluid for the workpiece material to extend tap life and improve thread quality. Do not force the tap if resistance increases suddenly, as this may indicate chip packing or an undersized pilot hole.