Accupro T1640427 Spiral Point Tap 1/4-28 3 Flute Plug

Product Description

The ACCUPRO T1640427 is a spiral point tap designed for threading 1/4-28 UNF holes in metalworking applications. Manufactured from HSS-E vanadium high speed steel with an oxide finish, this tap offers improved hardness and wear resistance over standard HSS tooling. The plug chamfer style allows for effective thread cutting in through-hole applications by pushing chips forward ahead of the cutting action. At 2.5 inches overall length with a 0.748-inch thread length and a 0.255-inch shank diameter, this tap is sized for use in standard drill presses, CNC machining centers, and hand-held tapping applications. Installation is typically performed by machinists and toolroom technicians working on production or repair threading operations.

This tap is suited for threading through-holes in ferrous and non-ferrous metals where a fine 28-thread-per-inch pitch is required. The 3-flute design with right-hand thread direction and H7 thread limit makes it appropriate for moderate-tolerance threading work in steel, cast iron, aluminum, and similar machinable materials. The spiral point geometry moves chips forward out of the cutting zone, making it particularly effective in through-hole production threading where chip evacuation is a priority. No coolant-through capability is present, so external cutting fluid application is recommended for best tool life.

Key Features

• HSS-E vanadium construction provides elevated hardness and heat resistance compared to standard high speed steel
• Plug chamfer style pushes chips forward, optimized for through-hole threading
• 1/4-28 UNF thread size with H7 thread limit for consistent tolerance control
• 3-flute design balances chip clearance and cutting edge support
• Oxide finish reduces friction and provides a degree of corrosion resistance during storage and use
• Right-hand thread direction, compatible with standard tapping equipment and tap handles

Compatibility

Designed as an OEM-style replacement or direct tooling tap for 1/4-28 UNF through-hole threading operations in standard machining and production environments.

Installation Notes

Taps should be installed by qualified machinists or toolroom personnel familiar with threading operations and proper speeds and feeds for the workpiece material. Always secure the workpiece and ensure the tap is properly aligned before beginning the threading cycle to avoid tap breakage. Apply an appropriate cutting fluid or tapping compound to the tap and workpiece before and during the operation. Follow applicable shop safety procedures and machine manufacturer guidelines when operating drill presses, mills, or CNC equipment.