Spi 21-251-4 Flat Contact Point Dial Indicator

Product Description

The SPI 21-251-4 is a flat contact point designed for use with dial indicators in precision measurement applications. Machined from black oxide steel, this contact point threads onto standard dial indicator stems using a 4-48 thread size conforming to AGD Group 1 specifications. The flat contact surface measures 3/16 inch in diameter with a contact point length of 0.25 inches. It is a direct-fit replacement or spare tip for technicians who rely on dial indicators for runout, flatness, and surface comparison measurements in shop, field, or inspection environments.

This contact point is suited for machinists, quality control inspectors, and precision measurement technicians working with AGD Group 1 dial indicators. The flat contact geometry is appropriate for measurements on flat, smooth, or broad surfaces where a spherical point would introduce unwanted rocking or contact error. It fits standard 4-48 threaded indicator spindles and is a commonly stocked replacement tip for production and inspection setups.

Key Features

• Flat contact point style for accurate surface contact on flat workpieces
• Black oxide steel construction for durability and corrosion resistance
• 4-48 thread size conforms to AGD Group 1 industry designation
• Contact point length of 0.25 inches (1/4 inch)
• Contact point diameter of 3/16 inch
• Single-piece package, no assembly required

Compatibility

Designed for use with dial indicators that accept 4-48 threaded contact points per AGD Group 1 specifications.

Installation Notes

Installation is performed by hand-threading the contact point onto the dial indicator spindle with a 4-48 thread. Zero the indicator after changing contact points to account for any length variation. Avoid overtightening, which can damage the spindle threads. Handle with care to preserve the flat contact surface geometry and measurement accuracy.