The Random Thoughts of a Geek heading for Banbury
The Random Thoughts of a Geek heading for Banbury

Bearing numbering system


If you do any amount of design with 3D printers, sooner or later you will find your self using bearings between two bits to help them move; normally you will reach for a “skateboard bearing” or a 608ZZ, however if you need a size that is not a 608ZZ the coding is a bit impenetrable

Type Series Bore Size Sealing Internal Clearance
1 Self aligning Ball Bearing 0 Extra light 4 4 mm Plain No shield C2 Less than standard clearance
2 Spherical Roller Bearing 1 Extra light thrust 5 5 mm Z One side shielded C3 More than standard clearance
3 Double Row Angular contact Ball Bearing 2 Light 6 6 mm ZZ Both sides shielded C4 More than standard clearance
4 Double row ball bearing 3 Medium 7 7 mm RS One side sealed
5 Thrust Ball Bearing 4 Heavy 8 8 mm 2RS Both sides sealed
6 Single row deep grove Ball Bearing 9 9 mm V One side non-contact seal
7 Single row angular contact Bearing 8 Extra thin section 00 10 mm VV Both sides non-contact seals
8 Felt seal bearing 9 Very thin section 01 12 mm DDU Both sides contact seals
32 / T Tapered Roller Bearing 02 15 mm NR Snap ring and groove
R Inch bearing 03 17 mm M Brass cage
N Cylindrical roller bearing 04 x5 (20 mm)
NN Double row roller bearing 05 x5 (25 mm)
NA Needle roller bearing 06 x5 (30 mm)
BK Needle roller bearing with closed end (Drawn cup) 07 x5 (35 mm)
HK Needle roller bearing with open ends (Drawn cup) 08 x5 (40 mm)
C CARB toroidal roller bearings 09 x5 (45 mm)
K Needle roller and cage thrust assembly 10 x5 (50 mm)
QJ Four-point contact ball bearing

The 608ZZ is a ‘Single row deep grove Ball Bearing’ ‘Extra light’ series bearing with a 8mm bore and Both sides shielded not necessarily encoded in the above is that the 608zz is 7mm thick and has an outside diameter of 22mm

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