Dial Gauge Simulator

This dial gauge simulator (dial indicator simulator) is a free online tool for practising how to read a dial gauge with 0.01 mm resolution. The dial gauge converts small linear plunger movements into amplified rotary needle movement on a graduated dial, making it essential for checking runout, flatness, parallelism, and Total Indicator Reading (TIR) in precision engineering. This simulator covers the 0–10.00 mm range with a revolution counter sub-dial and a Set Zero function. Designed for CNC machining students, quality control trainees, and engineering education metrology learners.

The simulator opens in Simulate mode with the needle at a default position. To begin:

• Grab and drag the needle (the cursor turns into a hand when it is over the needle) or use the up/down arrow keys to move the plunger. The ▲▼ spindle buttons on the canvas also allow fine control. Scrolling over the canvas scrolls the page as usual.
• The info row shows the reading in mm, micrometres (μm), and inches, with live conversions.
• Press the Set Zero button (or the X key) to zero the gauge at the current position — all subsequent readings are relative to this datum.
• Use the Zoom button to magnify the dial face for reading between 0.01 mm divisions.

In Simulate mode the plunger moves freely. The main dial has 100 divisions — each division represents 0.01 mm. One full revolution of the main needle equals 1 mm of plunger travel. The small revolution counter sub-dial tracks how many complete millimetres the plunger has moved, so the total reading = sub-dial (whole mm) + main dial (0.01 mm divisions). This mode helps you understand the gear-amplified mechanism and practise reading both the main needle and revolution counter together.

The reading breakdown strip below the info row shows this addition live: Revolution counter (whole mm) + Main dial (divisions × 0.01) = Total reading. Watch it while you move the plunger to build the habit of never dropping the whole-millimetre part — the most common beginner mistake.

Practice mode: The plunger is set to a random position. Read both the revolution counter and main dial, then type the total reading in mm into the input box. Click Check for instant feedback. Click New for another random reading. Your running score is tracked.

Quiz mode: Five questions test your dial gauge reading skills. After completing all questions, a results panel shows your score, star rating, and a question-by-question breakdown. Retake the quiz to improve your speed and accuracy.

Switch to Runout mode to see how a dial gauge measures Total Indicated Runout (TIR) on a rotating shaft. A cylindrical journal spins under the contact tip; because its rotation axis (the cyan cross-hair) is offset from its geometric centre, the tip — and therefore the needle — sweeps up and down once per revolution.

• Press Spin shaft to start rotation; press again to pause at any angle.
• Drag the Eccentricity slider (0.05–0.50 mm) to set how far off-centre the shaft runs.
• The bar tracks the live Min and Max readings and computes TIR = Max − Min, which equals exactly 2 × eccentricity.
• Press Reset to zero the captured swing and return the shaft to its start angle.

This is exactly how a machinist checks shaft or chuck runout on a lathe: mount the gauge, rotate the work slowly, and read the total needle swing.

Dial gauges are almost always used for comparative (relative) measurement rather than absolute measurement. The Set Zero function lets you:

• Pre-load the plunger against a reference surface or gauge block.
• Press Set Zero (or X key) to reset the display to 0.00 mm.
• Move to the workpiece — the reading now shows the deviation from the reference.

This is exactly how Total Indicator Reading (TIR) is measured: zero on one side, read the total swing. Practising zeroing in this simulator builds the habit needed for real surface plate inspection work.

• Always pre-load the plunger by at least 1–2 revolutions before zeroing — this ensures the plunger has travel in both directions for detecting positive and negative deviations.
• When checking runout, rotate the workpiece slowly and note the maximum and minimum readings — TIR = max − min.
• Mount the dial gauge rigidly using a magnetic stand or clamp — any vibration or loose mounting introduces false readings.
• In the simulator, practise reading both the main needle and the revolution counter sub-dial together to avoid dropping whole millimetres from your reading.