Osg 1755405 Spiral Flute Tap M4x0.70 Tin Vanadium Hss

Product Description

The OSG 1755405 is a spiral flute tap designed for cutting internal M4x0.70 metric coarse threads in a range of ferrous materials. It features three right-hand flutes at a 45-degree helix angle, which evacuate chips upward out of the hole — the standard approach for blind-hole tapping in tough materials. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a plug or taper style. A titanium nitride (TiN) coating reduces friction and extends tool life. The tap is ground from vanadium high-speed steel (HSS-V) and holds a 6H class of fit, the standard tolerance for general-purpose metric threads. Overall length is 2.125 inches with a 0.75-inch thread length.

This tap is suited for machine or hand tapping operations in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. The spiral flute geometry makes it particularly effective in blind-hole applications where chip clearance is a concern. It is used in machining, tool and die, maintenance and repair, and production threading operations where M4x0.70 internal threads are required to a 6H tolerance. The Series 343 designation indicates OSG's TiN-coated vanadium HSS spiral flute line.

Key Features

• 45-degree right-hand helix evacuates chips upward, ideal for blind-hole tapping
• Modified bottoming chamfer threads closer to the base of blind holes than plug-style taps
• TiN coating reduces friction and extends cutting life in ferrous materials
• Vanadium high-speed steel substrate provides toughness and wear resistance
• 6H class of fit meets standard metric thread tolerance for general fastening applications
• D4 thread limit for consistent fit across production runs

Compatibility

Designed for M4x0.70 metric coarse blind-hole tapping in stainless steel, high-carbon steel, low-carbon steel, and medium-carbon steel. Part of the OSG Series 343 TiN-coated vanadium HSS spiral flute tap line.

Installation Notes

This tap is installed and operated by machinists, tool and die makers, or maintenance technicians using a tapping machine, CNC machining center, or manual tap wrench. Always ensure the pilot hole is drilled to the correct diameter for M4x0.70 before tapping. Secure the workpiece and align the tap perpendicular to the hole surface to prevent tap breakage. Use an appropriate cutting fluid for the workpiece material to extend tool life and maintain thread quality.