Kennametal 5443835 Spiral Flute Tap 1/4-20 Bottoming 2B Hss

Product Description

The KENNAMETAL 5443835 is a spiral flute bottoming tap designed for cutting 1/4-20 unified threads in ferrous workpiece materials. Built from vanadium high speed steel with an oxide coating, it produces a 2B class of fit thread with right-hand direction. The 45-degree helix angle and fast flute style drive chips up and out of the hole, making this tap well suited for blind-hole tapping where chip evacuation is critical. It carries an H5 thread limit, providing controlled oversize tolerance for consistent thread fit. The overall length is 2.5 inches with a thread length of 0.63 inches (16 mm). This tap is sold individually and installed by machinists and maintenance technicians in production and job-shop environments.

The 5443835 is intended for tapping blind holes in steel, stainless steel, and cast iron where a full thread depth close to the bottom of the hole is required. The bottoming chamfer — typically 1 to 1.5 thread lead — allows threads to be cut very near the bottom of a blind bore. It is commonly used in CNC machining centers, turret lathes, and manual drill press setups where rigid tapping or tap holders maintain axial alignment. The 3-flute spiral design balances cutting load and chip clearance in medium-hardness ferrous materials.

Key Features

• Bottoming chamfer for maximum thread depth in blind holes
• 45-degree right-hand spiral flutes evacuate chips efficiently from blind bores
• H5 thread limit for controlled tolerance on 2B class of fit threads
• Oxide coating improves lubricity and surface hardness for longer tool life in steel and cast iron
• 3 flutes balance cutting load and chip clearance in medium-hardness materials
• No coolant-through design — suitable for flood coolant or cutting oil applied externally

Compatibility

Designed for tapping 1/4-20 unified national coarse threads in steel, stainless steel, and cast iron workpieces. Compatible with standard 0.255-inch shank tap holders and collet chucks used in CNC and manual machine tool setups.

Installation Notes

Taps must be installed by a qualified machinist or tooling technician using a properly sized tap holder or collet chuck that matches the 0.255-inch shank diameter. Ensure the spindle or tap holder provides adequate axial float or rigid-tapping synchronization to prevent tap breakage. Apply cutting oil or flood coolant appropriate to the workpiece material before tapping begins. Always de-energize or lock out the machine before changing tooling.