Spi 20-648-2 Drop Indicator Contact Point Extension

Product Description

The SPI 20-648-2 is a contact point extension designed for use with drop-style dial test indicators. It extends the reach of the contact point to 1, 2, or 3 inches, allowing technicians to access recessed surfaces, bores, and tight measurement locations that a standard contact point cannot reach. Machined from steel with a 4-48 thread, this extension mounts directly to the indicator spindle without adapters. Metrology technicians, toolroom machinists, and precision measurement professionals use this type of accessory when inspecting parts on surface plates, in fixtures, or on CNC machine beds.

This extension is suited for any application requiring extended reach on a dial test indicator. Common uses include runout checks on deep-bore features, flatness verification on recessed surfaces, and alignment work where the indicator body cannot be positioned close to the measurement point. It is equally at home in a production inspection environment, a toolroom, or a field calibration setup. The 1, 2, and 3 inch length options allow the technician to select the reach needed for the specific job without modifying the indicator itself.

Key Features

• Provides 1, 2, and 3 inch extension lengths for flexible reach on drop indicators
• Steel construction for rigidity and durability in measurement applications
• 4-48 thread mates directly with standard dial test indicator contact point spindles
• Enables access to recessed bores, deep features, and tight inspection locations
• Compatible with any test indicator on a dial indicator per manufacturer application note

Compatibility

Designed for use with any test indicator on a dial indicator equipped with a 4-48 threaded contact point spindle.

Installation Notes

Installation is performed by a metrology technician or machinist. Before swapping contact points or extensions, remove the indicator from any active clamping setup and ensure the indicator is not under spring preload stress. Thread the extension onto the 4-48 spindle by hand until snug, taking care not to overtighten and damage the fine thread. Verify indicator calibration and zeroing after any contact point change per standard metrology practice.