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The Tiniest Ball Bearings in the World

Ball bearings don’t come in all different shapes, but they do come in all different sizes.  If you know anything about ball bearings the miniature ball bearing will be reasonably familiar, but chances are you’re unlikely to have come across a ball bearing as small as the one featured in this article.  The world’s biggest ball bearing in use is 12 feet in diameter and weighs between 40,000 to 50,000 pounds, a pretty impressive size, but it’s arguably the tiniest ball bearing in the world which is the most astonishing feat of engineering.

Smaller than a grain of rice

Small bearings don’t come much smaller than this one in a fidget spinner (opens new window).  The bearing sits comfortably on a grain of rice with an outside diameter of 1.5mm, an inside diameter of 0.5mm and a width of 0.65mm.  It’s about the size of a lead of a pencil but can rotate impressively fast (over 5,000rpm).  The bearing is made from 440C stainless steel with six ball bearings.

Because it is so very tiny it has to be handled with extreme care.  This means the bearings are generally packaged in Class 100 clean rooms (very clean rooms indeed) and must be handled wearing surgical gloves because of the tiny amounts of acidic content on human skin.  During assemblage, workers must wear shoe covers, smocks and clean-room specification caps.  Makeup is band in these areas. 

This may give the impression that ultra-miniature ball bearings are very delicate, and though they are in manufacturing, once in place the bearings are designed to withstand harsh conditions. 

What are they used for?

These tiny bearings are commonly used in precise hand-held medical and dental equipment.  They’re also used in watches, clocks, micro-motors and micro-machines like model cars.  The bearings can withstand pretty high loads and are covered with special shielding to decrease contamination and improve strength.  The shield is designed to allow for lubricant whilst prevent debris getting in. 

This tiny ball bearing design proves how versatile the ball bearing is.  From the largest ball bearings in use which prevent earthquakes to the tiniest which allow medical professionals to save lives we really would be in a different place without our friend the ball bearing.  The tiniest ball bearing is just another one of those feats of engineering to marvel at.