Osg 1738901 Spiral Point Tap 5/8-11 Unc 3 Flute Hss

Product Description

The OSG 1738901 is a spiral point plug tap designed for threading 5/8-11 UNC internal threads in through-hole applications. Built from Vanadium High Speed Steel (HSS-E) with a steam oxide coating, it delivers improved lubricity and corrosion resistance during cutting operations. The plug chamfer distributes cutting forces over several leading threads, making it well suited for machine tapping in a production environment. With 3 flutes and an H5 thread limit, the tap holds close tolerance and produces consistent Class 2B fits. Overall length is 3.811 inches with a thread length of 1.137 inches and a shank diameter of 0.48 inches. Installed by machinists and maintenance technicians on CNC machining centers, drill presses, or tapping machines.

This tap is intended for right-hand threading in materials including low-carbon steel, medium-carbon steel, hardened steel, and stainless steel. It is a standard choice for through-hole tapping in general manufacturing, fabrication shops, and maintenance repair operations where a 5/8-11 UNC thread is required. The spiral point geometry pushes chips forward ahead of the tap, keeping the flutes clear during continuous machine tapping cycles. It is not designed for blind-hole applications where chip evacuation forward into the hole is not acceptable.

Key Features

• 5/8-11 UNC thread form, Class 2B fit with H5 thread limit for consistent tolerance control
• Vanadium High Speed Steel (HSS-E) construction for increased wear resistance over standard HSS
• Steam oxide coating reduces friction and improves chip flow during cutting
• Plug chamfer - approximately 3 to 5 threads - distributes cutting load and eases machine entry
• Spiral point geometry pushes chips forward, optimized for through-hole machine tapping
• Right-hand thread direction; no coolant-through feature

Compatibility

Designed for through-hole machine tapping in low-carbon steel, medium-carbon steel, hardened steel, and stainless steel. Fits standard tap holders accepting a 0.48-inch shank diameter in the OSG Series 300 product family.

Installation Notes

This tap should be installed by a qualified machinist or maintenance technician using a properly aligned tapping head or rigid tap holder. Ensure the spindle speed and feed rate are appropriate for the workpiece material and machine type before beginning the cycle. Apply cutting fluid or tapping compound rated for the material being threaded to extend tool life and improve thread quality. Do not reverse the tap under power without confirming the machine is set for synchronized reversing to avoid breakage.