Spi 21-239-9 Chisel Contact Point Dial Indicator

Product Description

The SPI 21-239-9 is a chisel-style contact point designed for use with dial indicators in precision measurement applications. Threaded at 4-48 to match AGD Group 1 dial indicator spindle standards, this contact point measures 0.625 inches in overall length and features a 60-degree point angle ground from black oxide steel. The chisel tip geometry makes it well suited for measuring in grooves, slots, and other features where a standard ball-tip contact point cannot make reliable contact. Metrology technicians and machinists install this type of accessory when a specific tip geometry is required for the workpiece being measured.

This contact point fits dial indicators that accept standard 4-48 threaded contact points, including those classified under AGD Group 1. It is commonly used in tool rooms, machine shops, quality control environments, and on the production floor wherever a dial indicator is mounted on a surface plate, magnetic base, or fixture. The chisel configuration is a practical choice for applications involving scribed lines, narrow slots, or angular surface checks.

Key Features

• Chisel contact point style for groove, slot, and angular surface measurement
• 4-48 thread size compatible with AGD Group 1 dial indicator spindles
• 0.625 inch (5/8 inch) contact point length
• 60-degree point angle for precise edge and slot contact
• Black oxide steel construction for durability and corrosion resistance

Compatibility

Designed for use with dial indicators that accept 4-48 threaded contact points, conforming to AGD Group 1 industry designation standards.

Installation Notes

Installation is performed by a metrology technician or machinist. Before swapping contact points, remove the indicator from any active fixture or clamp to prevent dropping or damaging the instrument. Thread the 4-48 contact point in by hand until snug, taking care not to cross-thread or over-torque the small-diameter thread. Verify the indicator reads zero correctly after installing the new contact point and before taking measurements.