This occurs unless the loads and radius are such that: If practicable, make ten readings. Active Risk Management Test Method E is also the preferred test method for use with any paper of nominal thickness from 2 to 26 mils using a specimen consisting of a single sheet. The force applied to the presser foot spindle and the weight necessary to just prevent movement of the pointer from a higher to a lower reading shall be more than the minimum permissible force speci? There may be instances, particularly when measuring very narrow strip specimens used for tensile tests, and so forth, when this requirement cannot be satis? The arithmetic average of the? In selecting loads to apply to the specimen, make a calculation to see if the resulting load and radius combination is too near the yield strength.
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Tojinn A number in parentheses indicates the year of last reapproval. Such a micrometer is described in Section 6 as Apparatus A. This will minimize any tendency to disturb the thermal equilibrium between the instrument and the ambient during the thickness measurements.
The condition of zero reading is satis? Do not stop the motor until all of the measurements are made. Make an initial reading 5 s after the presser foot has contacted the specimen surface. Avoid using measurement locations that are closer than mils from any specimen edge. Perform calibration procedures only after the instrument has been checked and found to meet the requirements of the pertinent preceding paragraphs of this standard.
Calculations using the equations in X1. There may be instances, particularly when measuring very narrow strip specimens used for tensile tests, and so forth, when this requirement cannot be satis? Observe this initial reading and then open the micrometer approximately 4 mils beyond the initial reading and move the specimen to the? This standard is subject to revision at any time by the responsible technical committee and must be reviewed every?
Current edition approved March 10, There will be different precisions between test methods and between materials. See also Note 6. An electronic instrument having a digital readout in place of the dial indicator is permitted if that instrument meets the other requirements of 6.
ASTM D — 99 Standard Test Methods for Thickness of Solid Electrical Insulation In selecting loads to apply to the asrm, make a calculation to see if the resulting load and radius combination is too near the yield strength.
Warning—Cleaning the presser foot and anvil surfaces as described in 7. The reader is directed to seek precision statements in those other ASTM standards that deal with speci?
If the radius of the hemisphere is reduced by 4, the load on the gage must be reduced by a factor of 2 r maintain the same penetration. If you feel that your comments have not received a fair hearing you should make your views known to the ASTM Committee on Standards, at the address shown below.
Use standard gage blocks or other metallic objects of known thickness. This is in contrast to previously held aastm of the necessity for maintaining constant average pressure. This occurs unless the loads and radius are such asm Failure to repeat the zero setting may be evidence of dirt on the surfaces. Test Method E is also the preferred test method for use with any paper of nominal thickness from 2 to 26 mils using a specimen consisting of a single sheet.
This condition necessitates the cleaning of these surfaces see 7. For other pressures, refer to Table A1. NOTE 5—Originally, the selection of stack versus single sheet specimens was based on data obtained using manually operated micrometers.
To avoid these costs, obtain procedures for cleaning such electronic gages from the instrument manufacturer. The values stated in each system are not necessarily exact equivalents; therefore, each system shall be used independently of the other.
Calculate the arithmetic mean of these ten readings. Diameter Spindles Pressure, psig 21 22 23 24 25 26 27 28 29 Weight, g clamping pressure of the arm support will not distort the micrometer frame. A standard specimen of known thickness of solid electrical insulation is not available for measurement of thickness by each of these test methods.
Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. Data for the plot may be obtained by making a series of measurements on a specimen using different weights with a? Use these test methods except as otherwise required by a material speci? Summary of Test Methods 4.
To calibrate a micrometer that will exert a pressure of Those micrometers were perceived to have greater measurement reliability at the wider d openings. The balls used commercially in ball bearings are almost perfect spheres having diameters constant within a few microinches.
An equation can be s expressing this idea using the equation for penetration written above: Design and construction of electrical machinery require that the thickness of insulation be known. The number of fringes cut by a straight line connecting the terminals of any fringes is a measure of the deviation from? Place the gage block on the anvil, and slowly lower the presser foot. The arithmetic mean of all thickness asym is the thickness of the specimen.
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