Cleveland C54890 Hand Tap 7/8-14 Taper Rh 3B H4 Hss

Product Description

The CLEVELAND C54890 is a 7/8-14 straight-flute hand tap designed for cutting internal threads in a range of ferrous and non-ferrous materials. Built from high speed steel with a bright uncoated finish, it runs in the right-hand direction and carries a Class 3B fit with an H4 thread limit. Overall length is 4.688 inches with a 2.22-inch thread length and a 0.697-inch shank diameter. The taper chamfer makes it suitable for starting threads in both blind holes and through-holes. Machinists and tool-and-die technicians rely on this tap for precise UNF threading operations on the shop floor or at the bench.

The C54890 is rated for use in alloy steel, carbon steel, aluminum, and free-machining stainless steel, making it a versatile option across general machining, maintenance, and repair applications. The 4-flute straight-flute geometry provides good chip control in through-hole conditions while maintaining thread quality in shorter blind holes. It is a Series 1001 tap sold individually and is appropriate for hand tapping operations as well as machine tapping setups where torque is carefully controlled.

Key Features

• 7/8-14 UNF thread size with taper chamfer for easy thread engagement
• High speed steel construction for durability across a broad range of workpiece materials
• Bright uncoated finish — suitable for use with cutting fluids appropriate to the workpiece material
• Class 3B fit with H4 thread limit for close-tolerance internal threading
• 4-flute straight-flute design supports both blind-hole and through-hole applications
• Right-hand thread direction; no coolant-through feature

Compatibility

Designed for blind-hole and through-hole threading in alloy steel, carbon steel, aluminum, and free-machining stainless steel workpieces requiring a 7/8-14 UNF internal thread.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap wrench or appropriate machine tapping chuck. Always secure the workpiece and align the tap perpendicular to the hole before starting. Apply a cutting fluid compatible with the workpiece material throughout the operation. Back the tap off periodically to break chips and prevent binding, particularly in deeper blind holes.