Osg 1405002108 Thread Forming Tap 4-40 Unc Bottoming Hss

Product Description

The OSG 1405002108 is a thread forming tap in the EXOTAP VP-NRT series, designed for cold-forming internal threads in ductile metals without cutting or producing chips. Built from powdered metal high-speed steel (PM-HSS) with a TiCN coating, this bottoming tap produces 4-40 UNC right-hand threads and is engineered for blind hole applications where maximum thread depth close to the bottom of the bore is required. The H4 thread limit designation ensures consistent, controlled fit tolerances. At 1.875 inches overall length, this tap is sized for standard machine tapping setups used by machinists and tool-and-die professionals.

This tap is suited for production and job-shop environments where blind hole threading in ductile materials is common. Rated for use in alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum, it covers a broad range of ferrous and non-ferrous workpiece materials. The bottoming chamfer (1 to 1.5 chamfered threads) allows threading to within a very short distance of the hole bottom, making it the correct choice when thread engagement must start near the blind end. The tapping depth reaches 0.559 inches, and the thread length is 0.2953 inches.

Key Features

• Cold-forming design eliminates chips, reducing tap breakage risk in blind holes
• Powdered metal HSS construction offers higher wear resistance than conventional HSS
• TiCN coating improves surface hardness and lubricity for extended tool life
• Bottoming chamfer (1 to 1.5P) enables threading close to the bottom of blind holes
• H4 thread limit for controlled 4-40 UNC fit tolerances
• Compatible with alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum

Compatibility

Designed for blind hole thread forming in ductile materials including alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. Material application codes P, M, and N apply. Not suitable for brittle materials or through-hole applications where chip formation is acceptable.

Installation Notes

Thread forming taps require a correctly sized forming tap drill hole - consult the appropriate forming tap drill chart for 4-40 UNC; the drill size differs from standard cut tap recommendations. Use a tapping lubricant or cutting fluid matched to the workpiece material. Secure the workpiece and use a tapping attachment or CNC rigid tapping cycle to maintain axial alignment and prevent tap breakage. Power down or de-energize any machine spindle before manually handling or changing the tap.