1. When reading calipers, first read the millimeter integer on the ruler based on the vernier zero scale line, that is, the integer part in millimeters.
2. Then see which scale line on the cursor is aligned with the scale line of the ruler body. If the sixth scale line is aligned with the scale line of ruler body, the decimal part is 0.6 mm (if there is no completely aligned line, take the line close to the alignment line for reading). If there is zero error, subtract the zero error from the above result (zero error is negative, which is equivalent to adding zero error of the same size).
3. The reading result is equal to the integer part plus the decimal part, and then minus the zero error.
4. Determine which scale line on the cursor is aligned with the scale line of the ruler body, and select three adjacent lines. For example, the left line is around the corresponding line of the ruler, the right line is on the left of the corresponding line of the ruler, and the middle line can be considered to be aligned. If you need to measure several times and take the average, you don't need to subtract the zero error every time, just subtract the zero error from the result.
Types and accuracy of calipers
There are three kinds of calipers: vernier calipers, dial calipers and electronic digital calipers.
1, 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. The principle of the cursor is to use the difference between the line spacing on the main ruler and the line spacing on the cursor to read the decimal part. There are three minimum readings: 0.02mm, 0.05mm and 0.01mm.
2. Calipers with instruments
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. Calipers with meters can solve the reading error problem of vernier calipers. Common minimum readings are 0.0 1mm and 0.02 mm.
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. There are also high-precision digital calipers with a resolution of 0.005mm, with an allowable error of 0.0 15 mm/ 150 mm, and multi-purpose digital micrometer with a resolution of 0.00 1mm (this is a national patent of Anyi measuring tools, and only they can produce it), with an allowable error of 0.005 mm/50 mm.
In addition, there are various non-standard special calipers, such as hook depth caliper for measuring groove depth, gear tooth caliper for measuring gear thickness, height caliper for measuring object height, and weld caliper (weld gauge) for measuring welding quality.
Special purpose calipers: sharp claw type, irregular and unknown size measurement. Measurement of position size of offset and unequal height area. Depth type, depth measurement. Thin slice and narrow groove diameter measurement.