Value Collection MSC-04439295 Straight Flute Tap 12-28 Unf

Product Description

The VALUE COLLECTION MSC-04439295 is a straight flute bottoming tap designed for cutting 12-28 UNF internal threads in through-holes and blind holes where full thread depth close to the bottom is required. Built from high-speed steel with a bright, uncoated finish, it delivers reliable performance across a range of ferrous and non-ferrous materials. The tap features 4 flutes, a right-hand thread direction, an H3 thread limit, and a 2B/3B class of fit, making it suitable for standard tolerance threading applications. Overall length is 2-3/8 inches with a thread length of 15/16 inches. This is a hand or machine tap for use by machinists, maintenance technicians, and tool-and-die professionals.

This bottoming tap is used when threads must extend to the bottom of a blind hole, or when a starter tap and plug tap have already been used to begin the thread. The 12-28 UNF designation identifies it as a Unified Fine thread, which is common in precision assemblies, thin-walled components, and applications requiring greater thread engagement per unit length compared to coarse threads. Typical applications include machine maintenance, repair work, fixture building, and production threading in shop environments.

Key Features

• Bottoming chamfer allows threading to the base of blind holes
• 4 straight flutes for chip clearance in standard threading operations
• High-speed steel construction supports use across common metals
• Bright, uncoated finish for general-purpose threading without coating buildup concerns
• H3 thread limit for consistent fit within 2B and 3B class tolerances
• Right-hand thread direction, standard for most fastener applications

Compatibility

Designed as an OEM-style replacement or standard shop tap for applications requiring 12-28 UNF internal threads with a 2B or 3B class of fit.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap wrench, tapping head, or CNC machine configured for the correct thread pitch. Always use appropriate cutting fluid for the workpiece material to extend tap life and reduce the risk of breakage. Ensure the tap is properly aligned perpendicular to the workpiece surface before starting the thread. For blind holes, back the tap out periodically to clear chips and prevent binding.