Osg 1757701 Spiral Point Tap 1/4-28 Unf Plug H3

Product Description

The OSG 1757701 is a spiral point plug tap designed for threading 1/4-28 UNF internal threads in demanding materials. Built from powdered metal and finished with a steam oxide coating, it delivers added lubricity and corrosion resistance compared to uncoated high-speed steel taps. The plug chamfer distributes cutting force across several leading threads, making it well-suited for through-hole applications. With an H3 thread limit and 3B class of fit, this tap produces threads within the tolerance range required for standard fastener assemblies. Machinists, tool-and-die technicians, and maintenance mechanics use this tap for production and repair work in metals that demand higher tool toughness and wear resistance.

This tap is rated for use in hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. Its spiral point geometry pushes chips ahead of the cut, keeping the flute path clear in through-hole setups. The right-hand cutting direction and standard shank make it compatible with conventional tap handles, tapping heads, and CNC rigid tapping setups. Series 312 designation places it within OSGs standard catalog of inch-series spiral point taps for trade and production environments.

Key Features

• 1/4-28 UNF thread form, right-hand cut, H3 thread limit
• Plug chamfer for through-hole threading applications
• Powdered metal construction for increased toughness in difficult alloys
• Steam oxide coating improves lubricity and reduces galling on stainless and high-nickel materials
• 3-flute spiral point design pushes chips forward, reducing clogging in through-holes
• No coolant-through requirement; suitable for use with cutting oil or tapping fluid

Compatibility

Rated for threading hardened steel, stainless steel, high-nickel alloy, titanium, alloy steel, and die steel. Designed for through-hole tapping in 1/4-28 UNF applications across production machining and maintenance repair operations.

Installation Notes

This tap is installed by machinists or maintenance technicians using a tap handle, tapping fixture, or CNC tapping head set to right-hand rotation. Always apply an appropriate cutting fluid or tapping compound before starting the thread to extend tool life and reduce the risk of tap breakage, especially in stainless steel and high-nickel alloys. Back out periodically when hand-tapping to break and clear chips. Inspect the tap for chipping or wear before each use; a damaged tap should not be returned to service.