Osg 1195402 Straight Flute Tap 1/4-28 Unf Plug Hss

Product Description

The OSG 1195402 is a straight flute tap designed for cutting internal threads in a range of ferrous and non-ferrous metals. It produces a 1/4-28 UNF right-hand thread to a 3B class of fit with an H3 thread limit, making it well suited for applications that require a standard tolerance fit. The tap features a plug chamfer, which distributes cutting load across several leading threads and works in both through-hole and moderately deep blind-hole applications. Constructed from high-speed steel, it delivers consistent performance across production and maintenance tapping operations. Overall length is 2.5 inches with a thread length of 1 inch.

This tap is used in general machining, maintenance, and fabrication environments where 1/4-28 UNF threads are required. The plug chamfer style is the most common choice for through-hole tapping and is appropriate for a wide range of shop and field repair scenarios. Machinists, toolmakers, and maintenance technicians routinely use this tap on manual machines, CNC equipment, and hand tapping setups.

Key Features

• 1/4-28 UNF thread form, right-hand, 3B class of fit
• H3 thread limit for standard tolerance control
• Plug chamfer distributes cutting load over multiple leading threads
• 2 straight flutes for chip clearance in shorter blind and through-hole applications
• High-speed steel construction suitable for a broad range of workpiece materials
• No coolant-through requirement - compatible with flood or manual lubrication

Compatibility

Rated for tapping aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. Designed as a standard 1/4-28 UNF plug tap replacement suitable for use in any setup requiring that thread form and a 3B class of fit.

Installation Notes

This tap is installed by licensed machinists, toolmakers, or qualified maintenance technicians using a standard tap wrench, tapping head, or machine spindle. Always use an appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. Secure the workpiece fully before tapping and ensure the tap is started square to the hole to avoid tap breakage. Follow shop safety procedures and applicable standards when working with rotating tooling.