Osg 1301500301 Spiral Flute Tap 5/8-11 Unc 4 Flutes Hss

Product Description

The OSG 1301500301 is a spiral flute tap designed for cutting 5/8-11 UNC right-hand internal threads in a range of ferrous materials. Built from high-speed steel with a steam oxide coating, it runs 4 flutes at a 45-degree helix angle, which evacuates chips upward out of the hole — a critical advantage in blind-hole and modified bottoming applications. The modified bottoming chamfer allows the tap to cut threads close to the bottom of a blind bore without the full starting length of a plug tap. Overall length is 1.875 inches, making it well suited for standard machining and tap-handle setups.

This tap is intended for threading operations in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel. The 2B class of fit produces standard tolerance threads appropriate for most fastener and general mechanical assembly applications. It is typically used by machinists, tool-and-die makers, and maintenance technicians in production, job-shop, and MRO environments. Coolant-through is not supported on this model, so flood or brush lubrication is the recommended approach when threading tougher alloys.

Key Features

• 45-degree right-hand spiral flute geometry evacuates chips out of blind holes during tapping
• Modified bottoming chamfer threads closer to the bottom of a blind bore than a plug chamfer
• High-speed steel construction provides wear resistance across a broad range of ferrous workpiece materials
• Steam oxide coating reduces friction and provides mild corrosion resistance during storage and use
• 2B class of fit produces standard-tolerance threads for general mechanical assembly
• Right-hand thread direction compatible with conventional tapping equipment and tap handles

Compatibility

Designed for cutting 5/8-11 UNC 2B class threads in alloy steel, carbon steel, cast iron, stainless steel, die steel, and hardened steel workpieces. Part of OSG Series 13015.

Installation Notes

Threading operations should be performed by a qualified machinist or maintenance technician using a properly sized tap wrench, tapping head, or CNC machine set to the correct spindle direction. Always apply a suitable cutting fluid or tapping oil matched to the workpiece material before starting — this is especially important when working with stainless or hardened steel. Secure the workpiece fully before beginning and verify that the pilot hole diameter meets the published tap drill recommendation for 5/8-11 UNC prior to tapping. Do not reverse the tap under load until the flutes have cleared chips to avoid breakage.