Zero calibration of external micrometers

 When using the micrometer, first check that the zero position is calibrated, therefore first loosen the locking device to remove the oil, especially the contact surface between the anvil and the micrometer screw, check that the end face of the micrometer barrel coincides with the zero mark on the fixed sleeve, if it does not, turn the knob until the screw is close to the anvil and then rotate the force measuring device. 

When the screw first touches the anvil, a clicking sound will be heard, then stop the rotation. If the two zero lines still do not coincide (the sign that the two zero lines coincide is that the end of the micrometer barrel coincides with the zero line of the fixed scale and the zero line of the moveable scale coincides with the horizontal cross line of the horizontal scale), loosen the small screw on the fixed sleeve, use a spanner to adjust the position of the sleeve to align the two zero lines, then tighten the small screw. Different micrometers from different manufacturers have different methods of zeroing, this is just one of the methods of zeroing. When checking whether the zero position of the micrometer has been calibrated, the screw must be in contact with the measuring anvil, occasionally it happens that the two do not separate when the force measuring device is rotated backwards, then the left palm of the hand can be used to press against the left side of the measuring anvil on the ruler frame, the right palm of the hand against the force measuring device, and then turn the knob with your fingers in a counter-clockwise direction, which can make the screw and the measuring anvil separate.

Reading of the outer diameter micrometer 

 When reading, first to the end of the differential cylinder prevail, read the index value of the scale line under the fixed casing (only read the integer in millimetres), and then to the horizontal line on the fixed casing prevail, read the standard line, read the index value on the movable scale, the reading should be estimated as 10/1 of the smaller scale, i.e. 0.001mm, if there is no upper scale between the end of the differential cylinder and the lower scale line of the fixed scale If there is no upper scale between the end face of the differential cylinder and the lower scale line, the measurement result should be the value of the lower scale line plus 0.5mm, plus the value of the movable scale. 

Some of the micrometer movable scale is divided into 100 equal points, the pitch is 1 mm, its fixed scale does not need half a millimetre scale, movable scale of each first point still said 0.01 mm, some of the micrometer, movable scale for 50 equal points, and fixed scale without half a millimetre scale, can only be estimated by eye; for the micrometer that has eliminated the zero error, when the front face of the differential cylinder exactly in the fixed scale under the scale line When the middle of the two lines, if the movable scale reads between 40-50, then its front end has not exceeded 0.5 mm, the fixed scale reading need not add 0.5 mm, if the movable scale reads between 0-10, then its front end has exceeded half of the two adjacent scale lines of the lower scale, the fixed scale number should add 0.5 mm.

Zero calibration of external micrometers

 When using the micrometer, first check that the zero position is calibrated, therefore first loosen the locking device to remove the oil, especially the contact surface between the anvil and the micrometer screw, check that the end face of the micrometer barrel coincides with the zero mark on the fixed sleeve, if it does not, turn the knob until the screw is close to the anvil and then rotate the force measuring device. 

When the screw first touches the anvil, a clicking sound will be heard, then stop the rotation. If the two zero lines still do not coincide (the sign that the two zero lines coincide is that the end of the micrometer barrel coincides with the zero line of the fixed scale and the zero line of the moveable scale coincides with the horizontal cross line of the horizontal scale), loosen the small screw on the fixed sleeve, use a spanner to adjust the position of the sleeve to align the two zero lines, then tighten the small screw. Different micrometers from different manufacturers have different methods of zeroing, this is just one of the methods of zeroing. When checking whether the zero position of the micrometer has been calibrated, the screw must be in contact with the measuring anvil, occasionally it happens that the two do not separate when the force measuring device is rotated backwards, then the left palm of the hand can be used to press against the left side of the measuring anvil on the ruler frame, the right palm of the hand against the force measuring device, and then turn the knob with your fingers in a counter-clockwise direction, which can make the screw and the measuring anvil separate.

Reading of the outer diameter micrometer 

 When reading, first to the end of the differential cylinder prevail, read the index value of the scale line under the fixed casing (only read the integer in millimetres), and then to the horizontal line on the fixed casing prevail, read the standard line, read the index value on the movable scale, the reading should be estimated as 10/1 of the smaller scale, i.e. 0.001mm, if there is no upper scale between the end of the differential cylinder and the lower scale line of the fixed scale If there is no upper scale between the end face of the differential cylinder and the lower scale line, the measurement result should be the value of the lower scale line plus 0.5mm, plus the value of the movable scale. 

Some of the micrometer movable scale is divided into 100 equal points, the pitch is 1 mm, its fixed scale does not need half a millimetre scale, movable scale of each first point still said 0.01 mm, some of the micrometer, movable scale for 50 equal points, and fixed scale without half a millimetre scale, can only be estimated by eye; for the micrometer that has eliminated the zero error, when the front face of the differential cylinder exactly in the fixed scale under the scale line When the middle of the two lines, if the movable scale reads between 40-50, then its front end has not exceeded 0.5 mm, the fixed scale reading need not add 0.5 mm, if the movable scale reads between 0-10, then its front end has exceeded half of the two adjacent scale lines of the lower scale, the fixed scale number should add 0.5 mm.