A micrometer is a precision measuring tool used in science, engineering, machining and home improvement to measure the diameter, thickness or length of an object. The micrometer primarily consists of a rotating barrel, sleeve and spindle contained within a sturdy frame. The barrel rotates on a precision screw with known thread dimensions which accurately tracks the travel distance. Placing the object within the frame and closing the spindle onto the object by rotating the barrel allows for measurements with submillimeter precision.
Things You'll Need
Micrometer Usage Instructions
Open the micrometer to its fullest. Place the object within the frame to confirm that the dimensions of the object are within the micrometer's limits
Turn the micrometer barrel clockwise to bring the spindle of the micrometer to the object. Stop rotating the barrel once the spindle comes into gentle contact with the object. Do not tighten the spindle onto the sample.
Lock the barrel in place by flipping the locking mechanism to the closed position.
Read the number below the measuring line. The ticks below the measuring line indicate whole millimeters. The ticks above the measuring line indicate 0.5 millimeters.
Read the number on the rotating barrel that aligns to the measuring line. Each tick indicates 0.1 mm. In most micrometers the barrel rotates between 0-0.50 mm. If the closest tick mark is below the measuring line, use the value indicated on the barrel for the tenths and hundredths measurement. If the closest tick mark is above the measuring line, add 0.5 to the value on the barrel.
Use the values obtained using the major tick marks and rotating barrel mark to obtain the overall size of the object to hundredths precision.
When using a micrometer for the first time practice using an object with known dimensions to understand the measurement system the micrometer uses. A ruler is a good aid for this.
Do not over-tighten the spindle onto the sample. This can damage the object and micrometer and affect the accuracy of the measurement