Accupro T4677165 Spiral Flute Tap 4-40 3 Flute Nitride

Product Description

The ACCUPRO T4677165 is a spiral flute tap designed for cutting 4-40 unified coarse internal threads in production and maintenance machining applications. Built from 3% Vanadium High Speed Steel (HSS), the tap delivers improved wear resistance and edge retention compared to standard M2 HSS. A nitride surface finish further extends tool life by reducing friction and resisting heat buildup. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a standard plug or taper tap, making it a practical choice where full thread depth near the floor of a hole is required. Three right-hand spiral flutes in a slow helix configuration pull chips up and out of the hole during the cut.

This tap is suited for threading cast iron components in manufacturing, maintenance, and repair environments. The 4-40 thread size is common in small fastener applications found in electrical enclosures, instrument housings, and light mechanical assemblies. The H5 thread limit designation indicates a tighter tolerance class, appropriate for fits requiring consistent thread form accuracy. Installation is typically performed by machinists, tool and die technicians, or experienced trade professionals using a tap wrench, tapping head, or CNC rigid-tapping setup.

Key Features

• 4-40 thread size with right-hand thread and right-hand flute direction
• 3% Vanadium HSS construction for enhanced wear resistance over standard HSS
• Nitride coating reduces friction and extends tool life in cast iron applications
• Modified bottoming chamfer allows threading close to the bottom of blind holes
• H5 thread limit for consistent, tighter-tolerance thread form
• Three slow-helix spiral flutes direct chip flow out of the hole during cutting

Compatibility

Designed for cutting 4-40 internal threads in cast iron workpieces. Suitable for use with standard tap wrenches and machine tapping heads configured for the appropriate shank diameter.

Installation Notes

Use the correct tap drill size for a 4-40 thread before tapping to ensure proper thread engagement and avoid tool breakage. Secure the workpiece and align the tap square to the drilled hole before applying cutting pressure. Apply an appropriate cutting fluid for cast iron to manage heat and chip evacuation. Follow shop safety protocols and always de-energize any equipment before tapping threaded holes in live assemblies.