The Macro Sensors BBP family of 3/8 inch diameter pencil-probe type gaging offers ultra-precise measurement of dimensions in a wide variety of Q.C., SPC, and industrial metrology applications. They utilize a linear ball bearing assembly precisely fitted to a hardened-and-ground, non-rotating probe shaft to minimize radial play and the effects of side loading. This results in the probes' exceptional repeatability of 0.000006 inch (0.15 µm).

One end of the probe shaft is coupled to the core of a friction-free LVDT sensor, which produces an output voltage that is very linearly proportional to the probe shaft position. The use of an LVDT for probe shaft displacement sensing eliminates any additional transducer errors due to friction, stiction, or mechanical hysteresis. The output from the LVDT can be connected to any standard LVDT signal conditioner and then passed to a gaging column display, digital readout, or computer based data acquisition system.

The other end of the shaft is internally threaded to accept an interchangeable tungsten carbide contact tip for wear resistance and reliability. For normal applications, the probe shaft is fully extended by a spring exerting a force of about 2.5 ounces (70 grams) at the probe's mechanical zero position. The entire bearing, shaft, and LVDT assembly are enclosed in a 3/8 inch diameter stainless steel tubular housing.

The front of a BBP LVDT gaging probe is attached to a rubber bellows that also covers the probe shaft, thereby preventing contaminants from entering the bearing. The rear end of the probe features a flexible coiled strain relief for the polyurethane-jacketed cable that connects the LVDT's output to the signal conditioner. Each probe is supplied with a replaceable end piece that converts the axial cable exit to a radial cable exit to minimize overall installed length in space-critical applications. Probe sealing meets the requirements of IEC IP-65.