Osg 1680500 Straight Flute Tap 3/8-32 Unef Plug Hss

Product Description

The OSG 1680500 is a straight flute tap designed to cut right-hand internal threads in a range of ferrous and non-ferrous metals. Built from high-speed steel with a bright, uncoated finish, this plug chamfer tap is suited for through-hole and moderate-depth blind-hole threading applications. It cuts a 3/8-32 UNEF thread form with 4 flutes, an H3 thread limit, and a 1-1/4 inch thread length. Overall length is 2-15/16 inches. The straight flute geometry makes it reliable in materials that produce short, breaking chips rather than long stringy ones.

This tap is appropriate for threading operations in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The plug chamfer - typically 3 to 5 threads of taper - allows the tap to start easily in a pre-drilled or reamed hole while distributing cutting load across the leading threads. It is well suited to manual tapping, tapping heads, and CNC rigid tapping cycles where a plug start is specified. The H3 thread limit provides the correct tolerance for standard UNEF thread fits in most production environments.

Key Features

• 3/8-32 UNEF thread form, right-hand direction
• Plug chamfer for easy starting in through and shallow blind holes
• 4 straight flutes - effective in short-chipping materials
• H3 thread limit for standard UNEF tolerance control
• High-speed steel construction, bright/uncoated finish
• No coolant-through - suitable for flood, mist, or paste lubricant applications

Compatibility

Compatible with aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces. Designed for standard 3/8-32 UNEF tapping applications per OSG Series 101N.

Installation Notes

Ensure the workpiece is securely fixtured and the tap drill hole diameter matches the required minor diameter for 3/8-32 UNEF threads before beginning. Power down or disengage the drive before changing or inspecting taps. Use appropriate cutting fluid or tapping paste for the workpiece material to extend tool life and improve thread finish. Follow shop-standard speeds and feeds for HSS taps in the target material - do not exceed the tool's rated surface speed.