Depth gaugeDepth gauge (vernier / dial / digital)

≡Standards, measuring range and accuracy

Standard

• JIS B 7518:2023 Geometrical product specifications (GPS) – Dimensional measuring equipment – Depth gauges (Mitutoyo's explanation covers the 2018 revision)

^[1][2][3]

Measuring range

• byMaker
  • Mitutoyo VD (527-101–105) 0〜150 / 200 / 300 / 600 / 1000 mm
  • Teclock dial type Stroke 10 / 20 / 30 mm (220–240 mm with extension rods)

^[5][6]

Resolution / graduation

• byMaker
  • Mitutoyo VD Minimum reading 0.02 mm (0.05 mm for VDS)

^[5]1 source, for reference

Accuracy (instrument error / maximum permissible error)

• Approach In JIS B 7518 (2018), "instrument error" became "indication error". The most important is the partial surface contact error E, which applies to depth measurement. Place two gauge blocks of the same size on a precision surface plate, seat the base measuring face on them with the beam measuring face on the plate, and subtract the gauge dimension from the indicated value
• byMaker
  • Mitutoyo VD15 (0–150 mm, 0.02 mm) E_MPE ±0.03 mm
  • Mitutoyo VD100 (0–1000 mm) E_MPE ±0.07 mm

^[2][3][5]1 source, for reference

▦Types

◎Part names and functions

◷How to read the scale

1. Reading a vernier type is the same as for a caliper (beam + vernier)^[3][4]
2. For the dial type, read the amount the contact projects from the reference surface using the short and long hands. The photo in the source shows 2.03 mmExample: 2.03 mm^[6]

✋Usage steps

1. Preparation: wipe the beam and sliding parts with a little micrometer oil, and clean the reference surface with a dry cloth^[4]
2. Operation check: move the base through its full travel. On a vernier type, take care that the beam does not come out of the base^[4]
3. Zeroing: set the origin on a surface with guaranteed flatness such as a precision surface plate (for the dial type, seat the base bottom on the origin surface, turn the bezel to set 0, and fix it with the clamp)^[4][6]
4. Measurement: with the reference surface firmly seated on the workpiece, extend the beam (contact) to the bottom and read^[4][6]
5. Reading: read from the front and watch for parallax^[4]

!Common measurement mistakes and countermeasures

✓Care, storage, inspection and calibration

Care and storage

• After use, check for damage and clean. If water-soluble cutting fluid got on it, apply rust prevention. Release the clamp and store away from high temperature and humidity. For long-term storage, apply rust prevention and remove the battery^[4]

Inspection and calibration

• Check the partial surface contact error with two gauge blocks of the same size on a precision surface plate^[2][3]
• When using extension rods, set the reference dimension with a master such as a gauge block^[6]

⇄Related instruments