Spi 21-274-6 Ball Contact Point 1.5mm 4-48 Dial Indicator

Product Description

The SPI 21-274-6 is a ball-style contact point designed for use with dial indicators in precision measurement applications. Machined from steel, this contact point features a 1.5 mm ball diameter and threads onto standard 4-48 indicator stems. It measures 0.3 inches in contact point length and is suited for surface measurement work where a small, consistent contact area is required. Metrology technicians, machinists, and quality control personnel use this type of contact point when inspecting parts on surface plates, fixtures, or inspection setups. Its compact ball geometry reduces the effect of surface irregularities on indicator readings.

This contact point is intended for dial indicators that accept the standard 4-48 thread. It is well suited for use in machine shop environments, quality labs, and tool rooms where dial indicators are used for part inspection, runout measurement, and comparative gauging. The ball contact style is especially useful on curved or irregular surfaces where a flat or pointed contact would introduce cosine error or damage the workpiece surface.

Key Features

• Ball contact style provides consistent, low-distortion contact on flat and curved surfaces
• Steel construction for durability and wear resistance in repeated measurement cycles
• 1.5 mm ball diameter for fine-resolution surface contact
• 0.3 inch contact point length for standard indicator reach
• 4-48 thread fits the most common dial indicator stems

Compatibility

Designed for use with dial indicators that accept a 4-48 threaded contact point.

Installation Notes

Installation requires only threading the contact point onto the 4-48 stem of the dial indicator by hand or with a small wrench — avoid overtightening, which can damage the stem threads. Ensure the indicator is zeroed after changing contact points, as a new contact geometry may shift the reference plane. Handle the ball tip carefully to avoid nicking or deforming the contact surface, which would compromise measurement accuracy.