Numbering Systematics :  Bearings are produced by major companies in the world and the same type of bearings are put on the market with a standard numbering system. 
This systematic has been standardized and published by ISO. Even in countries that do not use the metric system, these standard notations are followed.

The size systematic standardized by ISO was carried out simply as follows.

• The last two digits of the notation (far right) are used to indicate the inside diameter. 

• The number to the left of the inside diameter designation (third from the right) is used to indicate the outside diameter. 
  In this digit, the smallest outer diameter with the same inner diameter size is indicated by 8, and the digit in the digit changes as 8, 9, 0, 1, 2, 3, 4 as the outer diameter increases.

• The number to the left of the outside diameter designation (fourth from the right) is used to indicate the bearing width. The number 0 is used for the narrowest bearing width with the same inside diameter. As the bearing width increases, this figure is indicated as 0, 1,  2, 3, 4, 5. 
  (For thrust bearings, these numbers vary from thin to thick as 7, 9, 1.)

• The letter or numbers at the beginning (leftmost) of the bearing designation indicate the bearing type. 

• After a space is left to the right of the two numbers on the right reserved for the inner diameter in the bearing notation, the special shapes of that bearing are indicated with various numbers or letters. 

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Inner Diameter Indication :  There is a very simple rule about bearing inner diameter.
For bore diameters greater than 19 mm and less than 496 mm, 5 times the last two digits in the bearing designation gives the bearing inner diameter.
Example: NU 1088 cylindrical bearing inner diameter d= 88*5= 440 mm.

Since the last two digits in the display can be the largest 99, the last digits are written directly after the "/" sign for inner diameters greater than 5X99= 495mm. Example: 618/750  single row ball bearing with an inside diameter of 750 mm. These rules apply to all bearing types.

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Type Notation :  The starting characters in the notation determine the bearing type. Accordingly, if the first characters

      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  6 or 16  the bearing is a single row ball bearing
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  4 the bearing is a double row ball bearing. 
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  1 or 2 , the bearing is a self-aligning ball bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  7 , the bearing is an angular contact ball bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  3 , the bearing is a double row angular contact ball bearing.
      _cc781905-5cde-3194- ccde-3194- 136bad_531365cf If it starts with -bb3b-136bad5cf58d_  Q  the bearing is a four point contact ball bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  N  or 319, the bearing is a cylindrical roller bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  HK or N or RNA, the bearing is a needle roller bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  K  or T or 3, the bearing is a tapered roller bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  2, the bearing is a spherical roller bearing.
      _cc781905-5cde-3194- ccde-3194- 136bad_531365cf If it starts with -bb3b-136bad5cf58d_  5 , the bearing is an thrust ball bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  8 , the bearing is an axial roller bearing.
      _cc781905-5cde-3194-bb3b3b-136bad  _cc781905-5cde-3194- ccde-3194cf13631365c5cf3b31994cbdc13653155cf If it starts with -bb3b-136bad5cf58d_  29 , the bearing is an axial spherical roller bearing.

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Indication of Special Figures :  The alphabetic letters at the end of the bearing designation mean the following.

      _cc781905-5cde-3194-bb3b-1958cbad3db bearing bore :

      _cc781905-5cde-3194-bb3b-1378d_bad359b bearing :

      _cc781905-5cde-3194-bb3b-136bad5c

on the side of       _cc781905-5cde-3194-bb3b-1365c-nb3b-1365bd it has a slot

on the side of       _cc781905-5cde-3194-bb3b-36d58dcf It has a segment with

      _cc781905-5cde-3194-bb3b-1358d_badc-b1365c1365c spool : _cc781905-5cde-3194-bb3b-1358d_badc-b1365c13655c spool inside the cage

      _cc781905-5cde-3194-bb3b-3194c-136315cf3b-cc781905ccde-3194b-13635194cf bb3b-136bad5cf58d_ : Ball or rollers in alloy cage

      _cc781905-5cde-3194-bb3b-3194c-bb358dc-1363154cf bb3b-136bad5cf58d_ : Balls or rollers in Synthetic resin cage