1, caliper with instrument
A large hand-held length measuring tool takes the pitch of a precision rack and gear as a known length, and the indicator of the corresponding scale as the amplification, subdivision and indication part.
2. Vernier caliper
A ruler-shaped hand-held universal length measuring tool based on vernier principle for subdividing readings is mainly used for measuring inner diameter, outer diameter, step and depth. When measuring, the integer part of the magnitude is read from the main ruler, and the decimal part is read from the cursor.
3. Electronic digital calipers
A length measuring tool uses capacitive grating, magnetic grating and other measuring systems to digitally display measuring instructions. The commonly used resolution is 0.0 1mm, and the allowable error is 0.03mm/ 150mm.
Measuring principle
The principle of caliper is to use the difference between the line spacing on the main ruler and the line spacing on the cursor to read out the decimal part. For example, the line spacing on the main ruler is 1mm, and there are 10 squares on the cursor, and the line spacing is 0.9 mm. ..
If the cursor moves 0. 1mm, its 1 scribe line coincides with the 1 scribe line of the main ruler. If the cursor moves 0.2 mm, its second scribing line coincides with the second scribing line of the main ruler.
By analogy, the fractional part of the magnitude can be read from the coincidence of the cursor and the scribed line on the main ruler. The minimum reading of vernier caliper is 0. 1mm, which is the difference between the line distance of main ruler and vernier. Similarly, if the difference between their line distances is 0.05 mm or 0.02 mm (there are 20 squares or 50 squares on the cursor respectively), the minimum reading is 0.05 mm or 0.02 mm respectively.