Osg 2944001 Spiral Flute Tap 7/8-9 Unc Vanadium Hss

Product Description

The OSG 2944001 is a spiral flute tap designed for cutting right-hand internal threads to the 7/8-9 UNC standard. It features a modified bottoming chamfer, allowing threads to be cut closer to the bottom of a blind hole than a standard taper or plug tap. Built from vanadium high-speed steel (HSS) with a steam oxide coating, this tap offers improved lubrication retention and corrosion resistance during cutting operations. The 45-degree helix angle drives chips up and out of the flute efficiently, reducing the risk of chip packing in blind-hole applications. Machinists and tool-and-die professionals use this tap in production and maintenance settings where precision thread form and close-to-bottom reach are required.

The OSG 2944001 is suited for threading operations in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. The modified bottoming chamfer and spiral flute geometry make it particularly well-matched for blind-hole applications where full thread depth close to the hole bottom is needed. It is used in machine shops, maintenance facilities, and manufacturing environments requiring tight thread tolerance control. The H5 thread limit designates a controlled oversize tolerance appropriate for general-purpose threading in these materials.

Key Features

• Modified bottoming chamfer for threading close to the bottom of blind holes
• 45-degree right-hand spiral flute promotes efficient chip evacuation in blind-hole cutting
• Vanadium high-speed steel construction provides wear resistance across a range of ferrous materials
• Steam oxide coating improves lubrication retention and reduces galling during tapping
• H5 thread limit for controlled oversize tolerance and consistent thread fit
• No coolant-through feature — designed for use with external cutting fluid application

Compatibility

Designed for cutting 7/8-9 UNC right-hand internal threads in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces.

Installation Notes

This tap is installed and operated by machinists using a tap wrench, tapping head, or CNC machining center with appropriate tapping cycle settings. Before tapping, confirm the drill hole is sized correctly for a 7/8-9 UNC thread and that the workpiece is securely fixtured. Apply a suitable cutting fluid for the workpiece material to extend tool life and improve thread quality. Follow shop safety procedures and manufacturer guidelines when handling taps in hardened or difficult-to-machine materials.