Spi 20-345-5 Cupped Ball Contact Point 3mm Dial Indicator

Product Description

The SPI 20-345-5 is a cupped ball contact point designed for use with dial indicators in precision measurement applications. The contact point features a ruby ball tip measuring 3 mm in diameter and a 4-48 threaded shank that threads directly into the indicator spindle. At 0.5 inches in length, it provides a compact, repeatable contact surface for surface measurement and inspection tasks. The ruby material offers excellent wear resistance and is suited for frequent contact with hardened or abrasive workpiece surfaces. This type of contact point is standard equipment in quality control, machine tool setup, and metrology environments where consistent, accurate readings are required.

The 20-345-5 is intended for use with dial indicators conforming to AGD Group 1 specifications. It is commonly used in manufacturing, tool and die, inspection, and general metrology applications where a cupped ball contact point is needed to locate on a specific feature or provide a defined contact geometry. Compatible with dial indicators that accept a 4-48 threaded contact point.

Key Features

• Ruby ball tip for superior wear resistance and long service life
• 3 mm ball diameter provides consistent contact geometry
• 4-48 threaded shank for standard dial indicator compatibility
• 0.5 inch contact point length suits AGD Group 1 indicators
• Cupped ball style locates reliably on shafts and rounded surfaces

Compatibility

Designed for use with dial indicators that accept a 4-48 threaded contact point and conform to AGD Group 1 specifications.

Installation Notes

Installation is performed by a machinist, metrologist, or quality control technician. Thread the contact point into the indicator spindle by hand until snug — avoid overtightening, which can damage the fine 4-48 threads or the indicator body. Ensure the indicator is zeroed and recalibrated after changing contact points, as swapping tip geometry can affect measurement readings. Handle ruby-tipped contact points carefully to avoid chipping the ball against hard surfaces.