Osg 1121602 Straight Flute Plug Tap 3/8-24 Unf Hss

Product Description

The OSG 1121602 is a straight flute plug tap designed for cutting internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel, this tap carries a 3/8-24 UNF thread form with a 3B class of fit and an H3 thread limit, making it suitable for applications that require consistent, close-tolerance threads. The plug chamfer - typically 3 to 5 threads - allows entry into a through-hole or a blind hole with adequate clearance depth. With 4 flutes and a right-hand thread direction, it is paired with standard tapping fluids and a calibrated torque driver or tapping head for production or repair threading work.

This tap is used in machine shops, maintenance facilities, and production environments where 3/8-24 UNF threads are required. Typical applications include tapping holes in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The Series 101 designation identifies it within the OSG standard tap line. It is suited for both hand tapping and machine tapping operations where a plug-style entry is appropriate for the hole depth and workpiece setup.

Key Features

• 3/8-24 UNF thread form with 3B class of fit for standard close-tolerance thread production
• H3 thread limit for reliable fit across a range of tapping conditions
• Plug chamfer provides a moderate lead-in suitable for through-holes and sufficiently deep blind holes
• 4-flute straight flute design moves chips back through the flutes - best suited for through-hole tapping
• High-speed steel construction offers durability across the listed material applications
• Right-hand thread direction; compatible with standard right-hand tapping equipment and drivers

Compatibility

Designed for tapping 3/8-24 UNF threads in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Suitable for use with standard tapping heads, tapping attachments, or hand tap wrenches sized for the 3/8-inch shank.

Installation Notes

Threading operations should be performed by a qualified machinist or maintenance technician familiar with tapping feeds, speeds, and cutting fluid selection for the workpiece material. Secure the workpiece fully before tapping to prevent movement. Use an appropriate cutting fluid for the material being tapped - dry tapping is not recommended for steel. Ensure the tap is properly aligned with the drilled hole to avoid tap breakage and off-axis threads.