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 groove 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
