Miniature & Instrument Ball Bearings
Coding Classification of Bore and Outside Diameter
When required for selective assembly or other reasons, bores and/or outside diameters may be classified into coded size groupings within the tolerance range specified in this chart. Methods of measuring and determining classification size are specified in ABMA Standard, Section 12.1, and 12.2. Complete code designation consists of the bore code as the first digit or letter, and the outside diameter code as the second digit or letter. When only one dimension is classified, the other is denoted by “0”.
Table of Coding Classification Tolerance Ranges
|Size Tolerance* (from maximum)||.00005 Calib.||.0001 Calib.|
|maximum to –.00005||A||1|
|–.00005 to –.00010||B|
|–.00010 to –.00015||C||2|
|–.00015 to –.00020||D|
*Measurement in inches.
“C12” Bore falls between 0.00000 & -0.00010, O.D. falls between -0.00010 & -0.00020
“CAB” Bore falls between 0.00000 & -0.00005, O.D. falls between -0.00005 & -0.00010
“C10” Bore falls between 0.00000 & -0.00010, O.D. is not coded