Micrometer
 
     Micrometer measuring apparatus a class, outside micrometer
1 Definition: is the use of spiral vice principle, the two-foot shelf surface interval measurement readings from the outside dimensions measuring apparatus.
(2) Advantages: Use common, is an important precision measurement instruments. It has a small, rugged, high measurement accuracy, easy to use, easy adjustment and constant force measurement.
3 Measuring range: You can measure a variety of workpiece dimensions, such as length, thickness, diameter and protruding shoulder plate thickness or wall thickness, etc.
4 Accuracy: 0.01mm.
5 structure type:
6 reading methods:
(1) to read an integer - differential edge cylinder (or cone face) as integer mm reading instruction line, in a fixed casing exposed to the tick value is the measured mm-size and half-integer a few millimeters. As shown.
(2) read decimal - fixed line engraved on the casing as a fraction less than half a millimeter reading instruction line, read on fractional differential cylinder. Read decimal, see the fixed casing and differential cylinder vertical grooves carved on it a snap it knows the size of the measured fractional part.
(3) come to the measured size - the above two readings of the integer and fractional part of the sum, is the measured size.
7 How to use:
(1) to reduce the influence of temperature
   1) The use of a micrometer, to hand-hold thermal insulation.
   2) isothermal method using a micrometer and to maintain the same temperature of the device under test is measured.
(2) maintain a constant measuring force
   1) measurement, when the two measurements will be contact with the measured surface area, do not rotate the differential cylinder, only rotation force measurement device to switch hats, and other ratchet issue "card, the card" sound, then the readings.
   2) Adjust the distance is large, it should spin differential cylinder, rather than rotating force measurement device to switch hats; only when the measurement surface with quick access when the measured surface force measurement device. In this way, saving adjustment time, but also prevent premature wear ratchet.
   3) does not allow violently rotating force measurement devices, or by measuring the surface inertia toward the device under test, the measured force to a sharp increase, the measurement results are not accurate, but also easy bite micrometer screw.
   4) The back foot should be rotated differential cylinder, do not rotate the force measurement device to prevent loosening force measurement devices, zero impact.
(3) methods of operation
   1) measurement of large workpieces, it is best to put V-shaped piece of iron or platform, using both hands method: Hold the left foot shelf of thermal insulation, the right hand with two fingers rotating force measurement device to switch hats.
   2) measurement of small pieces, they can be fixed foot frame operation method: living with a soft foot pad things stand, gently clamped in the jaws or clamping frame (to prevent the fall break), the left hand hold the workpiece right hand operation with two fingers.