Cross referencing looks like a lookup problem and is really a measuring problem. Designations agree between manufacturers far less often than buyers expect.
Where Designations Agree
For metric ISO series, the base number describes type, dimension series and bore, and is broadly common across manufacturers. A 22220 is a 22220 in dimensional terms wherever it is made.
Where They Do Not
Suffixes are manufacturer specific. Cage material, clearance, precision, sealing and internal design codes differ between makers, and two parts with the same base number and different suffixes may not be interchangeable in the machine.
Inch tapered series, thrust TP and T series, and machine builder numbers such as the F- and Z- prefixed gear unit bearings are not decodable at all. They are matched against dimension tables.
A Routine That Works
- Record every marking on the part, including partial ones.
- Measure bore, outside diameter and width with a caliper, and record whether the dimensions look like round metric or round inch figures.
- Note the type, number of rows, cage material, rib arrangement and any seals or shields.
- Record the machine make, model and the position on the machine.
- Photograph the part from the side and from the face.
- Send all of it together rather than in stages.
Substitution Rules
Never substitute a lower load rating, a different clearance group or a different precision class silently. Where an exact equivalent does not exist, the sensible approach is to set out the dimensionally interchangeable options with their differences, and let the engineer responsible for the machine decide.
