ABMA 10A:2001 pdf free
ABMA 10A:2001 pdf free.Metal Balls for Unground Bearings and Other Uses
Measurement methods – size and size variation. For ball grades G3A-G200A, comparative methods shall be used. For ball grades greater than G200A, micrometers of known calibration status capable of measuring to 0.001 mm (or 0.0001 inch) may be used for determining size and variation of ball lot.
Masters for comparative measurements. Masters used for comparative measurements of size and variation of ball lot shall be made with masters traceable to the National Institute of Standards and Technology (NIST). The size of the master balls, or blocks shall be corrected to zero gage pressure, and to a temperature of 20°C (68°F).
Master materials. Master balls or blocks may be made of hardened chrome steel, tungsten carbide, or composite materials such as alumina oxide or zirconia. Hardness shall be 64 HRC or higher. When master balls are used for ball sizes of 1.5 mm (1/16 inch) diameter and smaller, master balls may be 440 stainless steel, 60 HRC or higher.
Master balls. The permissible diameter variation shall be one-tenth of the allowable diameter variation for the ball grade being measured, or 0.05 micrometers (2 micro-inches), whichever is larger. The calibrated diameter of the master ball is defined as the mean of at least twenty (20) randomly oriented diameters and must be known to an accuracy equal to plus or minus the magnitude of the permissible diameter variation of the master ball or plus or minus 0.08 micrometers (3 micro-inches), whichever is larger.
Master gage blocks. Master blocks used for comparative measurements shall have a known calibration status. Gage block sets shall be Grade 2, or better, as defined by Federal Specification GGG-G- 15C, except as noted below. When more than one block is used for comparative measurement, proper compensation, as defined in the calibration record of the set, shall be taken for each block used in the setup.ABMA 10A pdf free download.
