Kennametal 1542590 Hand Tap 3/8-16 Unc Bottoming Hss

Product Description

The KENNAMETAL 1542590 is a 3/8-16 UNC straight-flute hand tap designed for bottoming applications in ferrous and non-ferrous materials. Manufactured from high-speed steel with a bright uncoated finish, this 4-flute tap cuts right-hand internal threads to a Class 3B fit with an H3 thread limit. It measures 2.937 inches overall length with a 1.25-inch thread length, making it well-suited for tapping blind holes where full thread depth close to the bottom is required. Machinists and maintenance professionals install this tap by hand or with a tap wrench as the final step in a tapping sequence after a taper or plug tap has started the thread.

This tap is intended for use in cast iron and non-ferrous metals such as aluminum, brass, and copper alloys. The bottoming chamfer — typically 1 to 2 thread leads — allows threading to within a few threads of a blind hole bottom. It is appropriate for manual tapping operations in production, job shop, and maintenance-repair environments where a Class 3B thread tolerance is specified. The 4-flute straight-flute geometry provides good support and chip control in short-chipping materials common to cast iron and non-ferrous stock. Series 5305 and 5303 designations apply to this product family.

Key Features

• Bottoming chamfer for threading to near the bottom of blind holes
• 4-flute straight-flute geometry suited to short-chipping cast iron and non-ferrous metals
• High-speed steel construction for durability in manual tapping operations
• Bright uncoated finish — no coating buildup to affect thread tolerance
• Class 3B fit with H3 thread limit for controlled tolerance applications
• Right-hand thread direction, 3/8-16 UNC thread form

Compatibility

Designed for use in cast iron and non-ferrous metals. Compatible with standard tap wrenches and holders accepting a 0.381-inch shank diameter. Part of KENNAMETAL Series 5305 and 5303.

Installation Notes

This tap is intended for hand tapping by a qualified machinist or maintenance technician. Secure the workpiece fully before beginning and use a properly sized tap wrench to maintain axial alignment. Apply appropriate cutting fluid for the workpiece material — cutting oil for cast iron, light lubricant or cutting fluid for non-ferrous metals — to extend tap life and improve thread finish. When tapping blind holes, advance carefully and back off periodically to break chips and prevent tap breakage.