Several reading methods of steel tape measure
Direct reading method when measuring the steel tape zero scale alignment measurement starting point, proper tension (stretching force with steel tape tension or tension on the calibration ruler identification shall prevail, with the spring balance measure), direct reading measurement end point corresponding to the scale scale.
Precise steel tape factory and after a period of time must go through the verification and indicate the verification of temperature, tension and feet. Feet marked on the length of its nominal length, and the difference between the actual length is called length correction delta l ruler by different tension will make feet long. To avoid this change requires the use of steel tape according to the scale mark force of steel tape. At different temperature the foot will change with the temperature so it is necessary to use t as variable function to represent the feet long, this is the ruler length equation, its general form:
Indirect reading methodIn some parts of the steel tape can not be used directly, can use the ruler or ruler, the zero alignment measurement, ruler and measurement direction; steel tape measure distance to a whole scale ruler or ruler, with more than a long reading amount. (3).Some errors in measuring steel tape
