Consider marking it with the two right digits. They determine the main size of ball bearing – bore. When the hole diameter to 20 mm two rightmost digits indicate the following sizes: 00 – O 10 mm; 01 – O 12 mm; 02 – O, 15 mm and 03 – O 17 mm.
Multiply the two right digits in the designation to 5, with the hole diameter from 20 to 495 mm. the resulting work will give you the value of seat size bearing is its internal diameter. So if you see the designation of 08 numbers, then multiplying them by 5 to get bore diameter equal to 40 mm. correspond to the Numbers 20 O 100 mm, etc.
Note the third and seventh digits in the marking. Here you specify the series of the bearings: the third figure from the outside diameter, and the seventh width (height). Type diameter - this ultra-light, light, especially light, medium and heavy bearings. Width extra wide, wide, normal, narrow and very narrow bearings. Their width, as more indicated as follows: 7; 8; 9; 2; 3; 4; 5; 6. Normal values of widths of 0 and 1 are not indicated. The combination of the true values, marked first, second, then the third and the seventh shows the overall dimensions of the ball bearing rolling.
Take a look at the fourth number to the right indicating the type of the bearing: 0 - single row deep groove ball; 1 - double row spherical radial ball;2 - radial with short cylindrical rollers;3 - double row spherical radial roller;4 - roller with needles or long rollers;5 - roller with the winding rollers;6 - angular contact ball;7 - tapered roller;8 - ball thrust;9 - thrust roller.The fifth and sixth numbers in the designation indicate the design of the bearing.
If the above-mentioned parameters differ from the standard, consider an additional part marking. Additional left side indicates the accuracy class of the bearing. With the improvement of the accuracy classes marked in the following manner: 8; 7; 0; 6; 6; 5; 4; T; 2. Acceptable accuracy class starts with a zero, 8 and 7 classes – almost a waste. The middle ground in terms of price/quality you can get, with 6 precision class.