Spi 98-335-3 Magnetic Indicator Base 3.5 in Heavy-duty

Product Description

The SPI 98-335-3 is a magnetic indicator base designed to hold dial indicators and similar precision measuring instruments securely during inspection and layout work. The base features a 3.5-inch (88.9 mm) diameter magnetic footprint and a heavy-duty mechanical lock that provides a rigid, vibration-resistant hold on ferrous surfaces. An on/off switch allows the technician to place and reposition the base without disturbing the workpiece. The dovetail and stem mount accepts standard indicator holders, and the M8x1.25 threaded connection provides a secure attachment point. Fine adjustment capability allows precise positioning of the indicator tip. This tool is used by machinists, quality control technicians, and tool-and-die professionals.

The SPI 98-335-3 is suited for use on machine tool tables, surface plates, milling machines, lathes, and other ferrous work surfaces where stable indicator positioning is required. The heavy-duty mechanical lock is appropriate for environments where vibration or repeated repositioning could compromise measurement accuracy. The base height is 27 mm, keeping the overall profile low for setups in confined spaces.

Key Features

• 3.5-inch (88.9 mm) base diameter for a wide magnetic footprint and stable hold
• Heavy-duty mechanical lock for rigid, vibration-resistant positioning
• On/off switch for safe placement and repositioning on ferrous surfaces
• Fine adjustment capability for precise indicator tip positioning
• Dovetail and stem mount type accommodates standard indicator holders
• M8x1.25 threaded connection for secure indicator attachment

Compatibility

Designed as an OEM-style replacement or standard accessory base compatible with dial indicators and test indicators using M8x1.25 threaded stems and standard dovetail mounts on ferrous work surfaces.

Installation Notes

Installation is performed by machinists and metrology technicians. Before mounting, ensure the work surface is clean and free of chips or debris that could reduce magnetic holding force. Use the on/off switch to engage and disengage the magnetic base rather than sliding or pulling the base off a live surface. Verify the mechanical lock is fully engaged before taking measurements to prevent indicator shift.