Accupro 13085-01C Thread Forming Tap 5/16-18 Unc Bottoming

Product Description

The ACCUPRO 13085-01C is a thread forming tap designed for cutting 5/16-18 UNC internal threads in blind hole applications. Unlike cutting taps, thread forming taps displace material rather than remove it, producing stronger threads with no chips to clear. This tap is manufactured from powdered metal high speed steel and finished with a TiCN coating for extended wear resistance at elevated temperatures. The bottoming chamfer, with approximately 2.5 chamfered threads, allows threading close to the bottom of a blind hole. Machinists and tool-and-die tradespeople use this tap in CNC machining centers, manual mills, and drill presses where a clean, chipless thread form is required in ductile metals.

This tap is suited for threading ductile materials such as aluminum, mild steel, brass, and similar alloys where cold-forming is practical. The bottoming configuration makes it the correct choice when thread depth must extend as close as possible to the bottom of a blind bore. It produces a Class 3B fit with a thread limit of H5, making it appropriate for precision assemblies requiring tighter tolerances. Right-hand thread direction covers the majority of standard fastener applications in both production and maintenance shop environments.

Key Features

• Thread forming design displaces material rather than cutting, producing stronger threads and eliminating chips in blind holes
• TiCN coating improves surface hardness and heat resistance for longer tool life compared to uncoated HSS
• Powdered metal high speed steel construction provides finer grain structure and improved wear resistance over conventional HSS
• Bottoming chamfer (2.5P) allows threading to within a few threads of blind hole bottom
• H5 thread limit and Class 3B fit for precision thread forming in close-tolerance applications
• Single oil groove aids lubrication during the forming process

Compatibility

Designed for use in standard tap holders and collet chucks accepting a 0.318-inch shank diameter. Suitable for right-hand, 5/16-18 UNC blind hole threading in ductile metals on CNC and manual machine tools.

Installation Notes

Thread forming taps require a specific forming tap drill size, which differs from a standard tap drill - consult a forming tap drill chart for the correct hole diameter before use. Apply cutting oil or tapping fluid appropriate for the workpiece material to prevent galling and extend tap life. Secure the tap in a rigid holder to maintain alignment with the bore centerline and avoid tap breakage. Power down the machine and secure the workpiece fully before mounting or removing the tap.