The MAHR MarTest 802 NW is a mechanical 3D edge finder designed for rugged, repeatable workpiece zero-setting on CNC milling machines, machining centers, and EDM equipment. Its IP67-sealed construction withstands coolant immersion and chip exposure, making it suitable for automatic tool-changer (ATC) environments where the probe is stored in the magazine between cycles. A large high-contrast analog dial with 0.01 mm graduations provides clear, immediate reading of stylus deflection across a 6.6 mm working range in all three axes.

How does the 802 NW mechanical design compare to electronic touch probes?

Electronic touch probes require a battery, radio or infrared transmitter, and a receiver interface with the CNC controller — adding cost and complexity. The 802 NW is purely mechanical: stylus deflection moves a dial needle via an internal linkage, with no electronics, no batteries, and no machine interface required. The operator reads the dial directly while jogging the axes. For shops running a mix of manual and CNC machines, this self-contained operation means the same probe can move between machines without any setup or pairing procedure. The trade-off is that measurement requires operator attention rather than automated triggering — the 802 NW is a manual setup tool, not an in-process gauging sensor.

Contact Point and Maintenance

The standard carbide contact point (802 EWt, Mahr 4304320) provides a Ø 4 mm spherical measuring surface with 31 mm free length. An optional Ø 6 mm tip (802 NWt, Mahr 4304321) with 56.6 mm reach is available for applications requiring a larger ball or extended access. The probe tip is threaded for straightforward replacement when worn. No periodic recalibration is needed beyond the initial concentricity adjustment.