Basic designations - Special bearings
The basic designation of special bearings is usually the number of the drawing of the bearing. These Drawing Numbers are usually 6 or 7-figure numbers and do not generally give any indication of the bearing type, size or design.
Bearings, the design of which has been modified from the original design, often have a suffix A to E or a combination of these letters, e.g. AB, added to the original Drawing No. The meaning of these suffixes is specific to the actual bearing and reference must be made to the actual drawing.
More recently, Drawing Numbers have been prefixed by Bxxx, where B stands for bearing and the other three positions identify the bearing type. In some cases the fourth letter is omitted. Even more recently four figure numbers preceded by a prefix identifying the bearing type and separated from it by a hyphen, e.g. BB1-3001 have been introduced instead of the 6 or 7-figure Drawing Numbers.