Position is measured elsewhere
A machine tool positions its axes with linear scales and rotary encoders, and checks the workpiece with touch probes. Those are digital systems with their own interfaces, and there is no calculator for them on this site. What decides whether the measured position stays true over a shift is a second layer of sensors: temperature around the spindle and the structure, pressure in hydraulics and coolant, and vibration at the bearings.
Temperature: the spindle and the motor
Heat is the largest source of error in most machine tools. Steel grows by roughly 11 to 12 µm per metre for each kelvin, so a spindle housing that warms by 10 K moves the tool by an amount that matters at micrometre tolerances. Bearing seats and housings are therefore fitted with PT100 sensors, both to protect the bearings and to feed thermal compensation. A PT100 reads 123.242 Ω at 60 °C; the PT100 calculator converts either way and shows the tolerance of the element class, which is the limit on how well two sensors can be expected to agree.
Motor windings carry a PT1000 or a thermistor. A PT1000 reads 1573.25 Ω at 150 °C. Older drives were built for KTY silicon sensors, which follow a different curve; a PT1000 cannot be substituted unless the drive is set for it.
Pressure: hydraulics and coolant
Hydraulic clamping, tool release and counterbalance circuits are monitored with pressure transmitters or switches. A 0 to 250 bar transmitter at 12 mA reads 125 bar; the 4–20 mA converter does the scaling and flags currents outside the valid signal range, which is how a broken wire shows up.
Through-spindle coolant runs at high pressure, and its specifications mix units: 70 bar is 1015 psi. The pressure converter shows all units at once.
Vibration: bearings and balance
Spindle condition is monitored with an accelerometer on the housing. The sensor reports acceleration, while limits for machine vibration are usually stated as RMS velocity. The two are tied by frequency: at 200 Hz, the rotation frequency of a spindle at 12 000 rpm, a velocity of 1 mm/s RMS corresponds to 0.181 g peak and a displacement of only 2.25 µm peak-to-peak. The vibration converter converts between the three at any frequency and gives the output of an accelerometer of a given sensitivity.
The evaluation zones of ISO 10816-3 in that tool were written for industrial machines such as pumps and motors. Machine-tool spindles have their own criteria, which the tool does not include; use it here for conversion, not for a verdict.
Force: clamping and cutting
Clamping-force and some cutting-force sensors are strain-gauge bridges. A full bridge with a gauge factor of 2 gives 5 mV at 500 microstrain and 5 V excitation; the strain gauge bridge calculator shows this for any arrangement. Dynamometers for cutting-force research are mostly piezoelectric and work on charge, which is outside these tools.
Connections and sealing
Sensors inside the work area sit in coolant spray and swarf. A rating of IP67 covers temporary immersion but not high-pressure, high-temperature jets; that is IP69K, a separate test. The IP rating decoder explains what each code covers. For the port itself, G 1/4 and 1/4 NPT are close enough in diameter to be confused and do not seal against each other; the thread identifier tells them apart from a diameter and a pitch.
Updated October 11, 2026