Osg 1143500 Straight Flute Tap 9/16-18 Unf Bottoming Hss

Product Description

The OSG 1143500 is a straight flute bottoming tap designed for threading 9/16-18 UNF internal threads in a wide range of ferrous and non-ferrous materials. Built from high-speed steel (HSS) with a bright, uncoated finish, it features 4 flutes and a bottoming chamfer that allows threading close to the bottom of a blind hole. The H5 thread limit provides a tighter tolerance fit suitable for applications where thread accuracy is critical. With an overall length of 3-19/32 inches and a thread length of 1-21/32 inches, this tap is sized for standard machine and hand tapping operations in production and repair environments.

This tap is suited for tapping operations in aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel. The bottoming chamfer makes it the right choice for blind holes where a taper or plug tap has already started the thread and full thread depth near the bottom is required. It fits standard tap holders and collet chucks used in machine shops, maintenance facilities, and production lines. The right-hand thread direction is standard for the vast majority of UNF fastener applications.

Key Features

• Bottoming chamfer for threading to the bottom of blind holes
• 4 straight flutes for chip management in through and shallow blind holes
• H5 thread limit for controlled, tighter tolerance thread fit
• High-speed steel construction for durability across ferrous and non-ferrous materials
• Bright uncoated finish suitable for use with cutting fluids and tapping compounds
• Right-hand, 9/16-18 UNF thread form meets standard inch fastener requirements

Compatibility

Designed for use in standard tap holders, machine tap collets, and T-handle or tap wrench setups accepting a 0.429-inch shank diameter. Compatible with aluminum, cast aluminum, cast iron, low-carbon steel, medium-carbon steel, and high-carbon steel workpieces per OSG Series 101 application data.

Installation Notes

Secure the workpiece and ensure the correct pilot hole size for 9/16-18 UNF threads before tapping. When using in a machine setup, verify the tap holder is aligned to avoid bell-mouthing or tap breakage. Apply a suitable cutting fluid or tapping compound appropriate for the workpiece material. For blind holes, use a taper or plug tap to start the thread before finishing with this bottoming tap.