What is the dividing value of the spiral micrometer?
0.0 1 mm.
The complete number of turns of the screw is measured by the scribed lines on the fixed sleeve with an interval of 0.5 mm, and the part less than one turn is measured by the scribed lines around the movable sleeve, and the final measurement result is estimated to one decimal point. The first such measuring tool was patented by the French inventor JeanLaurentPalmer at 1848, and it is called "thread caliper with circular cursor holder". Today, we still use this typical feature to manufacture outside micrometer. When two American engineers Joseph. Brown and LucianSharpe visited 1867 Paris Exhibition. Their attention was attracted by Palmer's invention and they were very interested.
Use and maintenance
1. Check whether the zero bit line is accurate;
2. Wipe the measured surface of the workpiece during measurement;
3. When the workpiece is large, it should be measured on a V-shaped iron or flat plate;
4. Wipe the measuring rod and anvil clean before measurement;
operational approach
1) Before use, check the zero point:
Turn the fine-tuning knob D' slowly, so that the measuring rod (E) contacts the measuring anvil (A) until the ratchet makes a sound. At this point, the zero line on the movable ruler (movable sleeve) should be aligned with the reference line (long horizontal line) on the fixed sleeve, otherwise there will be zero error.
2) Hold the ruler frame (c) with the left hand, turn the coarse adjustment knob D with the right hand to make the distance between the measuring rod E and the measuring anvil A slightly larger than the measured object, put the measured object in, turn the protective knob D' until the ratchet wheel makes a sound, and turn the fixed knob B to fix the measuring rod and read.