Osg 1625512128 Thread Forming Tap 1/2-13 Unc 2B H8

Product Description

The OSG 1625512128 is a thread forming tap designed for producing internal threads without cutting, instead displacing material to create a stronger thread form. Built from cobalt high speed steel, this tap handles a broad range of materials and maintains edge integrity under the heat generated during form tapping. It is configured for 1/2-13 UNC threads with a 2B class of fit and features a semi-bottoming chamfer, making it suitable for threading holes that require thread engagement close to the bottom. The H8 thread limit accommodates standard tolerance requirements for 1/2-13 UNC applications. Machinists and toolroom technicians use this tap in both CNC and manual tapping operations.

This tap is suited for production and maintenance machining environments where cold-form threading is preferred over cut tapping. The semi-bottoming chamfer provides a middle ground between plug and bottoming configurations, allowing thread start-up with reasonable proximity to the hole bottom. Compatible material applications include aluminum, cast aluminum, carbon steel, alloy steel, die steel, hardened steel, stainless steel, high-nickel alloy, and titanium, giving this tap broad utility across job shop and production floor applications.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads with no chips
• Cobalt high speed steel construction provides heat resistance and extended tool life across tough materials
• Semi-bottoming chamfer allows threading close to the bottom of blind holes
• H8 thread limit meets standard tolerance requirements for 1/2-13 UNC Class 2B fits
• Right-hand thread direction for standard tapping operations
• 20 mm thread length and 150 mm overall length suit a wide range of workpiece depths

Compatibility

Designed for use in materials including aluminum, cast aluminum, carbon steel, alloy steel, die steel, hardened steel, stainless steel, high-nickel alloy, and titanium. Suitable for any application requiring 1/2-13 UNC internal threads to a 2B class of fit.

Installation Notes

Thread forming taps require a dedicated forming tap drill size, which differs from standard cut tap drill sizes — consult a thread forming drill chart before drilling the pilot hole. Apply a suitable tapping fluid or cutting oil appropriate for the workpiece material before and during tapping. Use a torque-controlled tapping head or CNC rigid tapping cycle where possible to avoid overloading the tap in harder materials. Secure the workpiece fully before operation and follow shop safety procedures for rotating tooling.