Osg 1771001 Spiral Flute Tap 3/8-16 Unc Bottoming 3B

Product Description

The OSG 1771001 is a spiral flute bottoming tap designed for threading 3/8-16 UNC holes in difficult-to-machine materials. Manufactured from powdered metal and finished with a steam oxide coating, this tap is built for applications where standard high-speed steel falls short. The spiral flute design pulls chips up and out of the hole, reducing the risk of chip packing in blind-hole applications. With a 3B class of fit and H3 thread limit, it produces threads to commercial tolerance standards. Overall length is 2-15/16 inches with a thread length of 1-1/4 inches. Licensed machinists and tool-and-die technicians are the primary users of this tap in production and maintenance environments.

The OSG 1771001 is suited for tapping stainless steel, hardened steel, titanium, and high-nickel alloys in both production and job-shop settings. The bottoming chamfer allows threading close to the bottom of a blind hole, making it the correct choice when full thread depth is required right to the floor of a bore. The 10-degree helix angle provides controlled chip evacuation without aggressive spiral action, which is appropriate for the tough materials this tap targets. It is used in CNC machining centers, CNC lathes with rigid tapping, and manual drill press or tapping operations.

Key Features

• Bottoming chamfer for full thread depth in blind holes
• Spiral flute geometry evacuates chips upward, reducing packing in blind-hole applications
• Powdered metal construction provides increased wear resistance over conventional HSS in hard and abrasive materials
• Steam oxide coating reduces friction and provides mild corrosion resistance during use
• H3 thread limit and 3B class of fit for standard commercial tolerance threading
• Right-hand thread, right-hand flute direction — compatible with standard CNC rigid tapping cycles

Compatibility

Designed for tapping 3/8-16 UNC threads in stainless steel, hardened steel, titanium, and high-nickel alloy workpieces. Part of the OSG Series 313NI tap line. Coolant-through is not supported on this tap.

Installation Notes

Installation is performed by qualified machinists or maintenance technicians using a tapping machine, CNC machining center with rigid tapping, or a dedicated tapping arm. Ensure the drilled hole is sized correctly for a 3/8-16 UNC tap prior to threading. When using in manual applications, apply appropriate cutting fluid rated for the workpiece material, particularly when working with stainless steel or titanium. Inspect the tap for wear or chipping between uses, as powdered metal taps used in hardened materials will dull before visible damage is apparent.