Osg 1140102 Straight Flute Tap 1/4-20 Unc 4 Flute Plug Hss

Product Description

The OSG 1140102 is a straight flute plug tap designed for cutting 1/4-20 UNC right-hand threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel (HSS), it runs in a 2B class of fit with an H5 thread limit, making it suitable for standard tolerance threading applications. The plug chamfer style provides a gradual lead-in of 3 to 5 threads, balancing starting ease with threading efficiency. With an overall length of 2.5 inches and a thread length of 1 inch, it fits standard tap handles and machine tool holders. Machinists, maintenance technicians, and toolroom operators are the primary users.

This tap is used in production machining, MRO maintenance, and general fabrication environments where 1/4-20 UNC threads are required. It performs in through-hole and blind-hole applications across a range of workpiece materials including aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The straight flute geometry makes it particularly effective in materials that produce short, brittle chips. It is suited to both hand tapping and machine tapping operations at controlled feeds and speeds appropriate to the workpiece material.

Key Features

• 1/4-20 UNC thread form with right-hand thread direction
• Plug chamfer (3 to 5 thread lead-in) for balanced starting and cutting performance
• High-speed steel construction for durability across a wide material range
• 4 straight flutes suited to short-chipping materials such as cast iron and carbon steels
• H5 thread limit and 2B class of fit for standard tolerance requirements
• No coolant-through design - compatible with flood coolant or cutting fluid applied externally

Compatibility

The OSG 1140102 is compatible with workpiece materials including aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel. It fits standard 1/4-inch tap holders, T-handle tap wrenches, and machine tool chucks sized for this tap shank diameter.

Installation Notes

This tap is installed by machinists and maintenance technicians using standard tap wrenches or machine tapping attachments. Always select the correct tap drill size for 1/4-20 UNC threads and ensure the workpiece is securely fixtured before tapping. Apply an appropriate cutting fluid for the workpiece material to extend tool life and improve thread quality. For blind holes, clear chips frequently to prevent tap breakage and verify hole depth before starting.