Osg 1625006403 Thread Forming Tap 6-40 Unf Cobalt Ticn

Product Description

The OSG 1625006403 is a thread forming tap designed for cold-forming internal threads in a 6-40 UNF configuration to a 3B class of fit. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips. The modified bottoming chamfer, with 2.5 to 3 chamfered threads, allows threading close to the bottom of blind holes. Constructed from cobalt high-speed steel and coated with TiCN, this tap is built for demanding materials and extended tool life. It carries the EXOPRO XPF trade name from OSG and fits within the Series 16250 product family. Licensed machinists, tool-and-die makers, and precision fabricators are the primary users.

This tap is suited for both blind hole and through-hole threading applications across a wide range of workpiece materials, including aluminum, cast aluminum, carbon steel, alloy steel, die steel, hardened steel, stainless steel, high-nickel alloy, and titanium. Material application codes P, M, N, and H confirm its range across ferrous and non-ferrous substrates. The 6-40 UNF thread form is common in precision assemblies where fine thread pitch is required for torque sensitivity or thin-walled components. Right-hand thread direction is standard.

Key Features

• 6-40 UNF thread form, right-hand direction, 40 threads per inch
• 3B class of fit with H3 thread limit for controlled tolerance
• Modified bottoming chamfer (2.5 to 3 chamfered threads) for close-to-bottom blind hole threading
• Cobalt HSS construction for heat resistance and durability in tough alloys
• TiCN coating reduces friction and extends tool life across ferrous and non-ferrous materials
• No-chip thread forming process produces stronger threads compared to cut-tap methods
• Compatible with blind hole and through-hole threading operations

Compatibility

Rated for use in aluminum, cast aluminum, hardened steel, carbon steel, alloy steel, die steel, stainless steel, high-nickel alloy, and titanium workpieces. Suitable for blind hole and through-hole threading operations requiring 6-40 UNF threads to a 3B class of fit.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is larger than a standard cut-tap drill size — consult the OSG Series 16250 drill chart for the correct pre-drill diameter before use. Adequate lubrication or tapping fluid is critical when forming threads in steel, stainless, or titanium to prevent galling and tap breakage. Secure the workpiece and ensure the tap is driven in true axial alignment with the pre-drilled hole; misalignment will damage the tap and the workpiece thread. Always verify spindle speed and feed rate are appropriate for the workpiece material before starting.