Spi 21-985-7 Test Indicator Ball Contact Point

Product Description

The SPI 21-985-7 is a ball-style contact point designed for use with dial test indicators in precision measurement applications. The contact tip is a 0.039-inch diameter ball machined from stainless steel, providing consistent, repeatable surface contact across a range of measurement tasks. The contact point length measures 0.73 inches, with a total package length of 0.75 inches. Machinists, toolroom technicians, and metrology professionals install this type of contact point when checking runout, flatness, bore alignment, or surface deviation on workpieces mounted in a lathe, milling machine, or surface plate setup.

This contact point is suited for precision inspection work in machine shops, toolrooms, and manufacturing quality-control environments. The ball-style tip is preferred when measuring curved or contoured surfaces where a flat or sharp-point contact would produce inconsistent readings. The 1.00 mm ball diameter makes it appropriate for applications requiring a small, defined contact area on fine-featured or delicate workpiece surfaces.

Key Features

• Ball-style stainless steel tip for consistent contact on curved and flat surfaces
• 0.039-inch (1.00 mm) ball diameter for fine-featured measurement applications
• 0.73-inch contact point length for standard reach in dial test indicator setups
• Stainless steel construction resists corrosion and wear in shop environments
• Sold individually, compatible with SPI Integral Series test indicators

Compatibility

Designed for use with the SPI Integral Series dial test indicators.

Installation Notes

Installation is performed by metrology technicians or machinists and requires no special tools beyond the contact point wrench or driver appropriate for the indicator model. Before swapping contact points, ensure the indicator is removed from active measurement duty and the spindle is protected from accidental loading. Thread the contact point in by hand first to avoid cross-threading, then snug with the appropriate tool. Do not overtighten, as the threaded contact point stem on precision indicators can be damaged by excess torque.