Guhring 9039890048260 Cobalt Sti Tap 10-32 Unf

Product Description

The GUHRING 9039890048260 is a cobalt spiral flute STI tap designed for cutting Spark-Tapped Insert threads in ferrous materials. Built to 10-32 UNF specifications with a 40-degree helix angle, this tap drives chips up and out of the hole during cutting, making it well-suited for blind-hole applications in alloy steel and unalloyed steel. The modified bottoming chamfer allows threading close to the bottom of a blind bore without sacrificing thread quality. A titanium nitride (TiN) coating reduces friction and improves wear resistance during high-cycle production use. Overall length is 2.5 inches with a 0.255-inch shank diameter.

This tap is used in machining, maintenance, and repair operations where STI thread inserts are required to restore or reinforce threaded connections. Its 3-flute, right-hand flute geometry with a 40-degree helix is particularly effective in short-chipping materials such as alloy steel and unalloyed steel. The 3B class of fit meets standard tolerance requirements for general-purpose threaded assemblies. Typical applications include production machining, toolroom work, and field repair of stripped or damaged threads using helical insert systems.

Key Features

• 10-32 UNF thread form for STI helical insert applications
• 40-degree helix angle drives chips out of blind holes during cutting
• Modified bottoming chamfer allows threading near the base of blind bores
• Cobalt construction provides heat and wear resistance in tough steels
• TiN coating reduces friction and extends tool life in high-cycle use
• Right-hand flute direction, 3B class of fit for standard tolerance assemblies

Compatibility

Rated for use in alloy steel and unalloyed steel. Designed as an STI tap following Series 3989 geometry for use with standard helical thread insert systems requiring a 10-32 UNF host thread.

Installation Notes

This tap should be installed and operated by a machinist or qualified maintenance technician familiar with tapping feeds, speeds, and cutting fluid requirements for cobalt tooling. Always secure the workpiece and use appropriate tapping fluid for the base material before starting the cut. Do not reverse the tap under power without confirming the machine setup supports it. Inspect the tap for wear or chipping before each use to avoid thread quality issues or tap breakage.