Accupro T1604442B Spiral Flute Tap 5/16-18 3 Flute Hss

Product Description

The ACCUPRO T1604442B is a spiral flute tap designed for threading 5/16-18 unified coarse holes in production and maintenance machining environments. Built from 3% Vanadium High Speed Steel (HSS) with an oxide finish, this tap delivers improved wear resistance and lubrication retention compared to standard HSS. The modified bottoming chamfer allows threading closer to the bottom of blind holes while maintaining chip control. With a 40-degree helix angle and fast flute style, it efficiently evacuates chips upward out of the hole, making it well-suited for interrupted cuts and tough materials. Overall length is 2.7188 inches.

This tap is rated for use in stainless steel and similarly demanding materials where chip evacuation is critical. The 3-flute, right-hand spiral configuration with a right-hand thread suits CNC machining centers, drill presses, and hand tapping operations requiring a 2B class of fit. Thread length is 14 millimeters. It is a single-piece item packaged individually and is appropriate for job shop, tool room, and production line applications where accurate internal threads are required in ferrous and high-alloy workpieces.

Key Features

• 5/16-18 UNC thread form with 2B class of fit for standard tolerance internal threads
• 3% Vanadium HSS construction for enhanced edge retention in stainless steel and alloy materials
• 40-degree helix angle promotes fast upward chip evacuation in blind-hole applications
• Modified bottoming chamfer allows threading near the bottom of blind holes
• Oxide finish improves lubrication retention and reduces galling
• Right-hand flute and right-hand thread, coolant-through not required

Compatibility

Designed as a direct-fit spiral flute tap for 5/16-18 UNC threading applications. Suitable for use in stainless steel per manufacturer material application rating.

Installation Notes

Installation should be performed by a qualified machinist familiar with tapping feeds, speeds, and cutting fluid selection for the workpiece material. Always ensure the tap is properly aligned with the pilot hole before applying torque to prevent tap breakage. Use an appropriate cutting fluid or tapping compound rated for stainless steel when threading difficult alloys. Inspect the tap for wear or chipping before each use and replace when thread quality degrades.