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How to Use an Indicating Micrometer
Guide · Updated October 28, 2026
An indicating micrometer has a normal micrometer head plus a dial indicator built into the frame behind a spring-loaded anvil. Set the spindle to the nominal size against a master, lock it, and then read each part's deviation on the dial.
Build the master
Use a gage block stack as the master. The free Gage Block Calculator builds the stack.
Step by step
- Clean the faces: Wipe anvil, spindle and the master.
- Build the master: Wring a gage block stack equal to the nominal size.
- Set to the master: Close the spindle on the master until the dial reads zero; lock the spindle.
- Set tolerance pointers: Move the pointers to the upper and lower limits.
- Retract the anvil: Press the button to retract the anvil and slide the part in.
- Release and read: Release the button; the dial shows plus or minus from nominal.
- Recheck the master: Every few parts, recheck zero.
Specs (Mitutoyo series 510)
Inch models: 0.0001 in graduation on the thimble, dial graduation 0.00005 in, indicating range ±0.0023 in, dial accuracy 0.00005 in, repeatability 0.00002 in, spindle feed error 0.00015 in. Metric: 0.001 mm head and dial, range ±0.06 mm, dial accuracy 1 µm, repeatability 0.4 µm. Retracting stroke is 2 mm; measuring force 5–10 N (Mitutoyo catalog).
Worked example: sorting 0.5000 ± 0.0002 in pins
Wring a 0.5000 in stack (or a 0.500 block). Set the mic to zero on it and lock. Pointers at +0.0002 and −0.0002. A pin reading +0.00015 is good; +0.0003 is oversize; −0.00025 is undersize. Because the spindle is locked, every pin sees the same anvil force from the spring, which is what makes the dial readings repeatable. Spindle feed error (0.00015 in) does not matter here: the spindle never moves after setting.
Three-wire thread measurement
Mitutoyo lists three-wire pitch diameter as a main use: set to the calculated M over a master, then sort threads by deviation. See three-wire measurement.
Why use one instead of a regular mic
Faster for batches, consistent force, and you read deviation directly. A digital mic gives absolute size but each reading depends on how you close the ratchet.
Common problems
Dial drifts: temperature; let master and parts soak. Zero shifts: spindle lock loose. Parts scratch: not retracting the anvil.
Tips
- Gage blocks: build a stack.
- Threads: three-wire threads.
- Temperature: temperature compensation.
FAQ
What is an indicating micrometer?
A micrometer with a dial indicator behind a retractable anvil.
What is the dial range?
±0.0023 in on Mitutoyo inch models; ±0.06 mm metric.
Dial graduation?
0.00005 in or 0.001 mm.
How do I set it?
Zero on a gage block master and lock the spindle.
Why use it?
Fast, repeatable comparison measurement.
Related guides and calculators
- How to Build a Gage Block Stack
- How to Measure Threads with Three Wires
- Gage Block Temperature Compensation in the Shop
- How to Check a Micrometer with Gage Blocks
- How to Read an Inch Micrometer
- How to Use Dividers for Layout
- How to Use Outside and Inside Spring Calipers
- All free machinist calculators
Build your stack in seconds
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