Scientific Cutting Tools BB156A Radial Relief Boring Bar

Product Description

The SCIENTIFIC CUTTING TOOLS BB156A is a radial relief boring bar machined from submicron-grade solid carbide for precision internal boring operations. It accepts a minimum bore diameter of 0.1550 inches and reaches a maximum bore depth of 0.75 inches, making it well suited for tight, shallow bores where rigidity and edge integrity are critical. The 3/16-inch shank diameter keeps the tool compact, and the 2-inch overall length provides a stable setup in standard boring bar holders. Right-hand cutting geometry is ground into the carbide blank for consistent chip clearance on conventional CNC and manual turning equipment. Machinists and tool-and-die professionals working with small-diameter internal features rely on this bar for repeatable dimensional accuracy.

This boring bar is used in small-bore internal turning applications on CNC lathes, manual engine lathes, and mill-turn centers. It is appropriate for finish and semi-finish boring of holes in the 0.155-inch range, typical in precision component manufacturing, instrument housings, hydraulic valve bodies, and similar tight-tolerance work. The submicron carbide grade holds up well in ferrous and non-ferrous materials where tool deflection and edge wear in small diameters are primary concerns. The BB1 series designation groups it with other SCIENTIFIC CUTTING TOOLS small-shank radial relief bars for consistent tooling setups across related bore sizes.

Key Features

• Submicron solid carbide construction provides high rigidity and wear resistance in small-diameter bores
• Minimum bore diameter of 0.1550 inches suits precision small-bore internal turning operations
• Maximum bore depth of 0.75 inches with a 2-inch overall length limits deflection in compact setups
• Right-hand cutting direction compatible with standard conventional and CNC lathe configurations
• 3/16-inch shank diameter fits common small-bore toolholders and boring bar holders
• Part of the BB1 series for consistent tooling across multiple bore diameter increments

Compatibility

Designed for use with boring bar holders accepting a 3/16-inch shank diameter; part of the SCIENTIFIC CUTTING TOOLS BB1 series of radial relief boring bars for small-bore internal turning applications.

Installation Notes

Installation is performed by qualified machinists on turning or mill-turn equipment. Secure the 3/16-inch shank fully in the toolholder to the recommended grip length before engaging the workpiece, and confirm the machine spindle is fully stopped and locked out before changing or adjusting tooling. Minimize bar overhang beyond the holder to reduce deflection at this shank diameter. Verify bore entry clearance against the 0.1550-inch minimum bore diameter before the first pass to avoid tool interference.