Type: 忖 - error value, mm; L - the length of the verification platform (i.e., the length of the feet with stress); 忖 P - tension deviation; E - elastic coefficient (2000 kg/was); F - steel tape ruler with cross sectional area (by foot with thickness and width). Through the experiment, the test of steel tape, of error of applying tension time also affect the value of error. Exert tension within a few minutes and exert tension within 12 hours, perception for reading reading have obvious differences, with a reading microscope readings can be found in a few hours.
Steel tape ruler with have certain personalised tailor tape elasticity, the deviation of tension, the length of the feet with stress directly affect the error value. Tension of the deviation, the length of the feet with stress and the relationship of error of the following type:
1, will be finishing * dense sent feet around a week work, make PI feet and workpiece by yan, keep the same height, both hands taut, about 20 Newton pulling force, rub back and forth a few times, can be obtained to measure reading values. Standard steel tape
2, in the measurement of more than 500 mm (孜) steel, can choose magnetic piece of secondary use.
(1) use a magnet first PI 'pay' end of solid on the surface of the workpiece, and then pull PI feet tightly around the workpieces, every distance of solid a magnet. Went to a lap later, will be the end of the scale of PI solid in the workpiece surface. At this time, his hands can loosen the PI ruler.
(2) at the end of the first, two pieces of magnet, sucked in the rest of the PI ruler on the surface of the magnet, on down to the bottom of the feet, solid and directly on the workpiece surface, used to support the feet of PI, prevent sagging due to 'body weight. Then PI with visual feet around the same height, and then will be the end of the first, two magnets were moved to the farther from the end of the first, the feet below the surface, the hands hold the feet of PI. Rub back and forth a few times, about 20 Newton pulling force, can be reading.
(3) illustrate reading method, as shown in figure. The retractable tape measure sewing feet of Lord feet on each case represents A 0. 5 mm diameter values, each lattice on the pay scale B on behalf of 0. 02 mm diameter values.
Legend says the workpiece diameter value is 1701. 16 mm. Pay scale zero point than the feet of 1701 mm, now find the pay scale and relative of the scribed line above the feet, the scribed line on the 0. 16 mm, 0. On 16 mm to 1701 mm, then get the diameter value is l7O1 artifacts. 1, 6 mm.
(4) after the measurement, will remain magnets fixed in the PI ruler on the surface, then pull 'side. While pushing the magnet roll until the roll out, put the magnet. This will prevent foot fall to the ground, avoids accidental injury large print tape measure of foot pain. And keep feet surface clean.
3, using the measurement of PI inside diameter, the applying of around 15 Newton thrust, make PI feet and artifacts on tight to keep the same height, and reading value add 0.5 mm can be concluded that the average diameter of workpiece.