Micrometer- Have a Great Scientific Impact in Today’s World

Micrometer sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw used widely for precise measurement of small distances in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers. Micrometers are often, but not always, in the form of calipers.

Micrometers, which are used to measure small distances or angles, come in three basic types: filar, ocular, and scale-division. The earliest of them, conceived by Lucas Brunn in Dresden and made by Christ of Treschler in 1609, employed two precise screws, and could measure small distances. The micrometer did not come into wide use until William Gascoigne's filar device for measuring the diameters of astronomical objects (1638–1639), which used screws driving fiducial knife-edges or wires placed at a telescope's focal plane.

Micrometers can be broadly classified into two.

1. External Micrometer and

2. Internal Micrometer

The external micrometer is the most commonly used one. This can be used to measure external dimensions like, length, width, thickness of a block, diameter of shaft etc. The internal micrometers are used to measure slot widths, whole sized etc. There are also depth gauges which use the micrometer heads to get accurate depth measurements. More micrometer in the coming posts.

Some micrometers are provided with a vernier scale on the sleeve in addition to the regular graduations. These permit measurements within 0.001 millimeter to be made on metric micrometers, or 0.0001 inches on inch-system micrometers.

The additional digit of these micrometers is obtained by finding the line on the sleeve vernier scale which exactly coincides with one on the thimble. The number of this coinciding vernier line represents the additional digit.

Thus, the reading for metric micrometers of this type is the number of whole millimeters (if any) and the number of hundredths of a millimeter, as with an ordinary micrometer, and the number of thousandths of a millimeter given by the coinciding vernier line on the sleeve vernier scale.

Outside Micrometer is the most common micrometer which uses the screw pair theory, to measure the distance between the two measuring face of the arch rack. But how to use it properly, and do as the following step, you will get it:

1.We should clean the micrometer before measuring, and then check all the parts to see if it’s flexible and reliable. It should turn flexible during the whole measuring trip, the movement should be smooth. The locking device should be reliable.

2. Check the zero position, so that the two measurements touch lightly without gap, then the zero reticle on the micro drum should be aligned with the vertical reticle on the fixed muffle.

3. We should clean the measuring surface of the work piece Does not allow to measure the abrasive surface, rough surface and the sharp edged surface.

4. When measuring, make the micrometer screw axis and the measured work piece in the same direction, do not tilt. Turn the ratchet wheel when the measuring surface in contact with the work piece surface. Read the value when the "click" sound happens. To get the readout on the measuring work piece directly. If it must be departed from the work piece. Lock the micrometer screw and then slip it out lightly.