Ball bearing

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Ball bearing

Vitamin

2011-04-11-rodamiento.jpg
Ball bearing are used for low friction movements across an axis.
Wikipedia Rolling-element bearing

A ball bearing is a bearing used for low friction movements across an axis. They are cheap and widely available, mostly from the skateboard industry.

Lubrication

Ball bearings are usually closed and have their own lubrication, so no additional lubrication is needed.

Name

The first digit of the model name refers to the kind of bearing, the second digit to its robustness. The third digit is usually the bore size in mm. Then follows the bearing type letters.

Types

There are several types of ball bearings:

Abbrev. Type Notes
Z Shielded, single  
ZZ Shielded, double Sufficient for most RepRaps.
RS Sealed, single  
2RS Sealed, double For keeping out generated dust and grit (e.g. from a Milling and Drilling Head)
V Non-contact seal, single  
VV Non-contact seal, double  
DDU Contact seals, double  
NR Snap ring and groove  
M Brass cage  

Sizes

The most common ball bearings are:

Abbrev. Inner D. Outer D. Thickness Notes
608 8 mm 22 mm 7 mm A common roller skate bearing used extensively in RepRaps.
626 6 mm 19 mm 6 mm  
624 4 mm 13 mm 5 mm  
623 3 mm 10 mm 4 mm  
603 3 mm 9 mm 5 mm  

The 608 size ball bearings in particular are extremely low cost. Their 8 mm bore size almost forces us to mount them on:

The 626 size ball bearing have a 6 mm bore size. We can mount them on:

The 624 bearing have a 4 mm bore size. We can mount them on:

The 626 and 624 bearings seem to cost more than 608 bearings, but M6 and M4 bolts and threaded bar cost less than M8 threaded bar and bolts, so it's almost a wash.

Vendors

Vendor From 8 mm 6 mm 4 mm 3 mm Additional notes
Charlie's 3D Technologies BE 608ZZ        
RobotDigg CN 608ZZ   624ZZ    
Paoparts FR 608ZZ 626ZZ 624ZZ 623ZZ
603ZZ
 
Reprapsource DE 608ZZ   624ZZ    
RepRap Kits UK 608ZZ   624ZZ    
3DMakerWorld US 608ZZ        
BOCA Bearings US many many many many  
VXB Ball Bearings US many many many many  
D&D-TOP Bearings CN many many many many  
Technobots UK 608ZZ
more
626ZZ
more
624ZZ
more
623ZZ
633ZZ
more
 
CIE Auto Source CN many many many many  
Wholesale Skateboard Bearings US 608SS       Minimum 80 pcs.
Imprimante 3D France FR 608ZZ
608ZZ (10 pcs)
626ZZ
626ZZ (10 pcs)
624ZZ
624ZZ (10 pcs)
623ZZ Paris area.

External Links