Osg 1170205 Straight Flute Tap 1/4-20 Unc Bottoming Tin Hss

Product Description

The OSG 1170205 is a straight flute bottoming tap designed for cutting internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel with a titanium nitride (TiN) coating, it threads 1/4-20 UNC right-hand internal threads to a 3B class of fit. The TiN coating reduces friction and extends tool life compared to uncoated HSS. With an H3 thread limit and 3 straight flutes, this tap is suited for through-hole and blind-hole applications where chips can be managed with a push-through or clearing pass. The bottoming chamfer allows threading to the bottom of a blind hole.

This tap is used in machining and fabrication environments where 1/4-20 UNC threads are required in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. It is sized for use in manual tap handles, tapping heads, or CNC tapping cycles. The Series 103 designation is an OSG standard product line. Typical users include machinists, tool and die makers, maintenance technicians, and general fabricators working on production or repair threading operations.

Key Features

• Bottoming chamfer allows threading to the bottom of blind holes
• TiN coating extends tool life and reduces heat buildup during tapping
• H3 thread limit provides consistent 3B class of fit tolerance
• 3 straight flutes for use in through-holes and short blind holes
• Compatible with aluminum, cast iron, low-, medium-, and high-carbon steel
• Right-hand thread direction, no coolant-through requirement

Compatibility

Designed as a standard 1/4-20 UNC bottoming tap for use in aluminum, cast aluminum, cast iron, high-carbon steel, low-carbon steel, and medium-carbon steel workpieces. Fits standard tap handles and machine tapping chucks sized for the 0.255-inch shank diameter.

Installation Notes

Tapping operations should be performed by a qualified machinist following safe workholding and tool-setup practices. Secure the workpiece firmly before beginning. Apply cutting oil or appropriate tapping fluid for the material being threaded to reduce tool wear and improve thread quality. When using in a machine tapping cycle, verify spindle RPM and feed rate are appropriate for the material and tap size before engaging. Inspect the tap for wear or chipping between uses, and replace when thread quality degrades.