KELIBRON Course · 5 lessons
Micrometers
Five lessons on the outside micrometer and its relatives: how the screw turns half a millimetre into hundredths, checking and setting zero, the ratchet and a steady measuring posture, the other micrometer types, and the mistakes that cost a reading. As each lesson goes live it pairs a guide, a demonstration and practice in the lab.
For students, apprentices and inspectors who can read a caliper and need finer readings. Take the caliper course first.
Lessons
Lesson 1
The screw and the reading
Read a mechanical micrometer and know where its hundredths come from.
You will be able to
- Relate the 0.5 mm pitch and the 50 thimble divisions to the 0.01 mm scale interval.
- Read sleeve whole and half millimetres plus thimble divisions × 0.01 mm.
- Spot the half-millimetre line and know when to add 0.5 mm.
Learn this lesson in the lab → Read the guide: How to read a micrometer
Practise in the lab
Lesson 2
Checking and setting zero
Check a micrometer’s zero before use and correct for a zero error.
You will be able to
- Check zero with clean faces, closing through the ratchet or on a setting standard.
- Read a zero error with its sign and subtract it from the reading.
- Tell how zero is set on a 0–25 mm micrometer and on larger ranges.
Learn this lesson in the lab → Read the guide: Micrometer zero check and zero error correction
Practise in the lab
Lesson 3
The ratchet and measuring posture
Measure with the same light force every time and the micrometer square to the part.
You will be able to
- Explain why the last closing goes through the ratchet.
- Hold the micrometer square to the surface and find the largest diameter.
- Measure a thin shim flat, away from burrs, at several points.
Learn this lesson in the lab → Read the guide: Micrometer technique: ratchet, posture, thin parts
Practise in the lab
Lesson 4
Depth, inside and bore micrometers
Choose the micrometer type for a depth, a groove or a bore.
You will be able to
- Name the main types of micrometer and what each measures.
- Read the lab’s inside micrometer and three-point bore micrometer.
- Set the lab’s three-point bore micrometer on its setting ring before measuring a bore.
Learn this lesson in the lab → Read the guide: Types of micrometer
Practise in the lab
Lesson 5
Common micrometer mistakes
Recognise the mistakes that spoil a micrometer reading.
You will be able to
- Avoid misreading the half millimetre.
- Explain how dirt, tilt and too much force change the reading.
- Judge a part only from a valid reading against its limits.
Learn this lesson in the lab → Read the guide: Common micrometer mistakes
Practise in the lab
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