Osg 1009000 Straight Flute Tap 7/8-9 Unc Hss Plug Chamfer

Product Description

The OSG 1009000 is a straight flute tap designed for cutting internal threads in a range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright uncoated finish, it is configured in a 7/8-9 UNC thread form with a plug chamfer and 4 flutes. The plug chamfer provides 3 to 5 chamfered threads, making it suitable for through-hole tapping where the tool can pass fully through the workpiece. Overall length is 4-11/16 inches with a thread length of 2-7/32 inches. The H2 thread limit keeps tolerance tight, which is critical for consistent fit across production runs. Machinists, tool-and-die makers, and maintenance technicians are the primary users.

This tap is suited for tapping applications in both job-shop and production environments. Its material compatibility spans aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel, covering the most common workpiece materials encountered in general machining and maintenance work. The right-hand thread direction is standard for the majority of threaded fastener applications. The straight flute geometry works best in through-hole applications where chips can evacuate freely ahead of or behind the tap. No coolant-through feature is present, so conventional flood or mist coolant delivery methods apply.

Key Features

• 7/8-9 UNC thread form with right-hand direction and H2 thread limit for controlled tolerance
• Plug chamfer (3-5 thread lead) suited for through-hole tapping operations
• 4-flute straight flute geometry for chip clearance in through-hole cuts
• High-speed steel construction provides durability across a broad range of workpiece materials
• Bright uncoated finish - no coating buildup to affect thread tolerance
• Compatible with aluminum, cast iron, low-, medium-, and high-carbon steel workpieces

Compatibility

Designed for use in standard 7/8-9 UNC through-hole tapping applications across general machining, maintenance, and production environments. Compatible workpiece materials include aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel per OSG Series 101 specifications.

Installation Notes

This tap should be installed in a rigid tapping holder or tapping head appropriate for the machine spindle in use. Always secure the workpiece firmly and ensure the hole is drilled to the correct tap drill diameter for a 7/8-9 UNC thread before tapping. Apply appropriate cutting fluid for the workpiece material to reduce friction and extend tool life. Inspect the tap for wear or chipping before each use - a damaged tap can seize in the bore and damage the workpiece.