Accupro T2634162B Spiral Flute Tap 4-40 3 Flute 2B Hss

Product Description

The ACCUPRO T2634162B is a spiral flute tap designed for cutting 4-40 unified fine threads in a modified bottoming chamfer configuration. Built from 3% vanadium high speed steel (HSS) with a bright, uncoated finish, this tap delivers consistent thread quality in a compact 1.87-inch overall length. The spiral flute design pulls chips up and out of the hole during tapping operations, making it well suited for blind-hole applications where chip evacuation is critical. It is sized for small-diameter, fine-pitch work typical in precision fabrication, electronics, and light mechanical assembly. Machinists and toolroom technicians are the primary users.

This tap is intended for use in both manual tapping operations and low-speed machine tapping setups. The 4-40 thread size and modified bottoming chamfer make it particularly useful when threads must be cut close to the bottom of a blind hole. The 2B class of fit specifies a standard tolerance range for general-purpose threaded assemblies where moderate clearance is acceptable. Right-hand flute direction and right-hand thread orientation are standard for conventional tapping in steel, aluminum, brass, and similar materials.

Key Features

• Modified bottoming chamfer allows thread cutting close to the bottom of blind holes
• Spiral flute geometry promotes upward chip evacuation, reducing tap breakage risk in blind-hole work
• 3% vanadium high speed steel construction provides wear resistance and toughness in ferrous and non-ferrous materials
• 2B class of fit meets standard tolerance requirements for general-purpose threaded fastener applications
• 33-degree helix angle optimizes chip flow in medium-length flute configuration
• Bright, uncoated finish is compatible with a wide range of cutting fluids

Compatibility

Designed as a standard 4-40 spiral flute tap suitable for use in machine tapping chucks, tap handles, and tapping attachments that accept a 3.58 mm shank diameter.

Installation Notes

This tap should be installed by a machinist or toolroom technician using an appropriately sized tap wrench, tapping head, or CNC tapping chuck. Ensure the workpiece is securely fixtured and the tap is aligned perpendicular to the work surface before applying cutting torque. Apply a suitable cutting fluid for the workpiece material to extend tap life and improve thread finish. Never reverse a tap under power without confirming the machine supports rigid tapping or a tension-compression floating holder is in use.