ASME B89.15 pdf free download

ASME B89.15 pdf free download MEASUREMENT OF PLAIN EXTERNAL DIAMETERS FOR USE AS MASTER DIscS oR CYLINDRICAL PLUG GAGES
4REQUIREMENTs oF MASTER DIscs AND
cYLINDRICAL PLUG GAGES
4.1 General
The capability of measuring equipment and tech-niques toachieve a high order of precision in thecalibration of master discs or cylindrical plug gages isiimited by relevant features and conditions of the gageto be measured. These are discussed in paras.4.2through 4.8.
4.2 Design
The design and proportion specifications for gageblanks are given in ASME/ANSI B47.1.
4.3 Material
The material，including coatings or wear inserts.ofmaster discs or cylindrical plug gage blanks shall befree from inclusions or other imperfections that wouldaffect surface texture. The material shall respond toapplicable hardening and stabilizing processes to permitfinishing to the essential surface texture and to assuredimensional stability. Finished surfaces shall have aminimum hardness equivalent to 60 on the Rockwellc Scale. Master gages shall not be subjected to anyquick aging or shock treatment as a check of stability.
4.4 Surface Texture
The surface texture shail be consistent with the classtolerance of the gage.Table 1 lists maximum roughnessvalues expressed in arithmetic average (R)roughnessvalues. ASME B46.l shall be consulted for referenceinformation.
4.5 Geometric Requirements
4.5.1 General. The diameter will be measured perpara. 6 of this Standard. Typical acceptance criteriafor geometric requirements are diameter measurementsspaced approximately 90 deg apart in each of threeplanes: the midsection,and each end，located 1.6 mm’6 in.) from inside the ends of corner radii or chamfers.Two-point diameter measurements will not detect theeffect that odd-numbered or irregular lobing has onsize.Diameter measurements taken at multiple locationsmay not fully detect ovality, even-numbered lobing. orstraightness deviation.
lf the gage is measured with nonstandard techniques,such as multiple-point methods or unusually wide planeanvils，the values in Table 3 may not be appropriate.
The purchaser and the manufacturer should consult on acceptable limits in these cases. The practical application of Table 3 would be to compare the measured size of a gage to the prescribed size plus (for GO) or minus (for NOGO) the tabulated tolerance (for bilateral gages, plus and minus one-half the tabulated tolerance). The measured size should fall within the size range thus specified. The practical application of Table 2 would be to compare all the measurements taken on a gage and find the difference between the largest and smallest measurements. The difference should not exceed the tabulated value. NOTE: ASME Y14.5M RULE删(para. 2.7.1) DOES NOT APPLY DUE TO THE LIMITATIONS OF PRECISION MEASURING EQUIPMENT AND THE INABILITY TO CORRELATE COMPOS- ITE FORM DEVIATIONS WITH ABSOLUTE SIZE. (Perfect form at maximum material condition is not required.)
4.5.2 Roundness. Deviations in roundness can be determined at three planes (see para. 4.5.1) perpendicular to the axis of the gage, using a chart type precision spindle instrument. The out-of-round condition shall not exceed the value shown in Table 2. ANSI B89.3.1 shall be consulted for measurement information. Plug gages used other than as diameter masters, such as limit gages, shall be evaluated by criteria applicable to the intended use.
4.5.3 Straightness and Taper. Deviations from surface element straightness can be determined by making axial tracings approximately 90 deg apart using a profile type instrument. The determined value shall not exceed the tolerances listed in Table 2. Taper is measured as the gradual increase or decrease in diameter over the full length of the gage.
4.6 Face Perpendicularity of Master Discs The faces of master discs are not required to be ground square to the gaging surface. However, proper measurement techniques must be followed (see para. 6).
4.7 Face Perpendicularity of Plug Gages Plug gage ends are not required to be perpendicular (square) or controlled. Remove sharp edges to prevent damage to the product being measured and to provide. for the user’s safety. If depth steps are required, ends shall be ground. See Appendix C. 4.8 Tolerance Classes Master discs and cylindrical plug gages are graded into classes identified by XXx, XX, X, Y, Z, and ZZ