Micrometer

The micrometer in question is a measuring instrument for "external" that allows you to make measurements with a precision which is  1/100 of a millimeter.

Curiosity

• The micrometer [M] is a unit of measurement equal to one millionth of a meter: How was it that the measuring instrument has the nearest one hundredth?
• Why to take a measurement you act on a micrometer screw to the rod moving from which it takes its name.

How is it made

The instrument is formed by a frame arc - A - at whose end there is the anvil - B - and the movable rod - C - where will position the workpiece to be measured. The ends of the anvil is, both of the movable are flat, parallel and made in hard metal, which guarantees the durability and wear resistance.

On the right side we find the compass graduated - D - where is engraved a linear scale consists of a line, called "lubber line", above which there millimeters and half millimeters below.

Inside we find the micrometer screw - E - Mobile connected to the rod that allows her to move back and forth in pleasure.

The thimble- F - allows to carry out the measurements and if desired, blocking the movable rod with a locking device - G - to a quota sample, to use it as a kind of gauge fixed.

The clamping device - H - consists of a knurled nut and a torque limiter: the latter serves to prevent the pressure of the movable can overcome a force value of 10 newtons, thus avoiding a possible damage to the instrument and of incurring an incorrect size.

Feature

The field of measurement, in micrometers most used in the workshop is limited to 25 millimeters, irrespective of the flow, to avoid defects in construction of the mechanism that may distort the measurement. In our micrometer 25-50 the value of minimum capacity is 25 and the maximum is 50 with the field of measurement equal to 25 millimeters.

How does it work

The measurement of the thickness of a workpiece is performed by pressing it between the faces of measurement, by the use of the torque limiter or clutch, which will turn to empty once reached the right pressure. To obtain a complete measurement, you have to add up the cents recorded on scale drum, always in the line of faith, with millimeters and half millimeters previously read on the compass graduated.