Osg 1749001 Spiral Flute Tap 1-12 Unc 4 Flutes Modified Bottoming

Product Description

The OSG 1749001 is a spiral flute tap designed to cut 1-12 UNC internal threads in ferrous materials. It features four right-hand spiral flutes with a 45-degree helix angle, which efficiently evacuates chips upward during the tapping cycle. The modified bottoming chamfer allows threading closer to the bottom of a blind hole compared to plug or taper styles. Manufactured from vanadium high-speed steel and finished with a steam oxide coating, the 1749001 is built for tapping stainless steel, high-carbon steel, medium-carbon steel, and low-carbon steel. It carries a 3B class of fit and an H4 thread limit for consistent tolerance control. Machinists and tool-and-die professionals install this tap in CNC machining centers and manual tapping operations.

The OSG 1749001 is suited for production tapping in aerospace, automotive, and general metalworking environments where 1-12 UNC threads are required in tough ferrous alloys. The spiral flute design makes it especially effective in blind-hole applications where chip packing is a concern. Its 5.125-inch overall length provides clearance for deep-reach applications, and the 0.48-inch shank diameter is compatible with standard tap holders and collet chucks sized for large-diameter taps.

Key Features

• 45-degree right-hand helix angle promotes reliable upward chip evacuation in blind holes
• Modified bottoming chamfer allows threading near the bottom of a blind hole
• Vanadium high-speed steel construction for increased wear resistance in hard ferrous materials
• Steam oxide coating reduces friction and provides mild corrosion resistance during storage and use
• H4 thread limit and 3B class of fit ensure consistent tolerance across production runs
• Compatible with stainless steel, high-carbon, medium-carbon, and low-carbon steel applications

Compatibility

Designed for cutting 1-12 UNC internal threads in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Intended for use in standard tap holders and collet chucks that accommodate a 0.48-inch shank diameter.

Installation Notes

This tap should be installed by qualified machinists familiar with threading operations and proper cutting fluid application for the workpiece material. Always ensure the spindle or tapping head is powered off and at a complete stop before loading or removing the tap. Use appropriate tapping fluid or cutting oil rated for the base material to extend tool life and maintain thread quality. Verify that the holder torque and feed rate are set within the machine manufacturer guidelines for the shank diameter before beginning the tapping cycle.