Cleveland C54886 Straight Flute Tap 7/8-9 Unc Bottoming Hss

Product Description

The CLEVELAND C54886 is a straight flute bottoming tap designed for cutting 7/8-9 UNC internal threads in both blind holes and through-holes. Built from high-speed steel (HSS) with a bright/uncoated finish, this tap delivers reliable thread cutting performance across a range of ferrous and non-ferrous materials. The bottoming chamfer style allows threading to the bottom of a blind hole, making it the right choice when full thread depth is required close to the base. With 4 flutes and an H4 thread limit, it holds tight tolerances consistent with a 3B class of fit. Overall length is 4.688 inches with a 2.22-inch thread length.

This tap is suited for shop and field machining applications involving alloy steel, carbon steel, aluminum, and free-machining stainless steel. The 7/8-9 UNC thread form is a standard coarse-pitch configuration widely used in structural fastener applications, heavy equipment, and general fabrication. Machinists and tool-and-die professionals select the bottoming chamfer when a through-tap or plug tap cannot complete the job due to depth constraints. It is part of the Cleveland Series 1003 standard tap line.

Key Features

• Bottoming chamfer for threading to the base of blind holes
• 4 flutes with H4 thread limit for 3B class-of-fit tolerances
• High-speed steel construction for durability across multiple material types
• Bright/uncoated finish — no coating buildup to affect thread tolerances
• Right-hand thread direction, 7/8-9 UNC form
• No coolant-through requirement — compatible with standard flood or manual lubrication

Compatibility

Designed for cutting 7/8-9 UNC internal threads in alloy steel, carbon steel, aluminum, and free-machining stainless steel. Suitable for both blind hole threading and through-hole threading applications.

Installation Notes

A licensed machinist or qualified shop technician should install this tap using appropriate tapping fluid or cutting oil matched to the workpiece material. Secure the workpiece fully before starting the tap to prevent thread misalignment. Use a properly sized tap wrench or CNC rigid-tapping setup; do not force the tap past its thread limit. For blind holes, verify hole depth before threading to avoid bottoming the tap against uncut material.