Kennametal 1540437 Hand Tap 4-40 Unc Plug Rh Hss

Product Description

The KENNAMETAL 1540437 is a straight-flute hand tap designed for cutting 4-40 UNC internal threads in a wide range of materials. Manufactured from high-speed steel (HSS) with a bright, uncoated finish, this tap is built for durability and consistent thread quality in production and maintenance environments. It features a plug chamfer, right-hand thread direction, and an H2 thread limit for close-tolerance fitment to 2B and 3B class-of-fit requirements. The overall length is 1.88 inches with a thread length of 0.563 inches. Licensed machinists, toolroom technicians, and maintenance professionals use this tap for hand-tapping operations where precise thread form is required.

This tap is suited for threading 4-40 UNC holes in cast iron and non-ferrous metals. The plug chamfer — typically 3 to 5 threads of lead — makes it appropriate for through-holes and for starting threads in blind holes after a taper tap pass. It belongs to the Kennametal Series 5305 and 5303 product families. Typical applications include instrument panels, electrical enclosures, small mechanical assemblies, and any application calling for a 4-40 machine screw thread.

Key Features

• 4-40 UNC thread form with right-hand cutting direction
• Plug chamfer for general-purpose through-hole and blind-hole threading
• H2 thread limit for 2B and 3B class-of-fit tolerance control
• High-speed steel construction for wear resistance across ferrous and non-ferrous workpieces
• Bright, uncoated finish — no heat-treat distortion concerns for close-tolerance work
• 3-flute straight-flute geometry for reliable chip clearance in hand-tapping operations

Compatibility

Designed for use in cast iron and non-ferrous metal workpieces requiring 4-40 UNC internal threads to 2B or 3B class-of-fit standards. Part of the Kennametal Series 5305 and 5303 tap families.

Installation Notes

Tap installation should be performed by a qualified machinist or toolroom technician using a properly sized tap wrench or tapping fixture to maintain thread alignment. Always secure the workpiece before tapping and use an appropriate cutting fluid for the workpiece material to extend tap life and improve thread finish. Back the tap off periodically to break chips when threading deeper holes. Inspect the tap for wear or chipping before each use — a damaged tap can seize in the hole and require extraction.