How smooth is a ball bearing?

How smooth is a ball bearing?

The best generally available ball bearings are grade 3, which are spherical in sizes up to 2 inches in diameter to +-0.000003″. The lowest grade, 1,000, are spherical to +- about 0.001″. Earth varies in elevation from a low in the Marianas trench to a high at Everest; about -36,000 feet to + 29,000 feet.

Are ball bearings perfectly round?

If you have ever rolled a couple of those little metal balls found in a ball bearing around in your hand, you have noticed how perfectly round and incredibly smooth they feel. A wire of metal approximately the diameter of the finished ball is fed through a heading machine.

Is Earth a perfect ball?

Even though our planet is a sphere, it is not a perfect sphere. Because of the force caused when Earth rotates, the North and South Poles are slightly flat. Earth’s rotation, wobbly motion and other forces are making the planet change shape very slowly, but it is still round.

How hard is a ball bearing?

Steel uses what is called the Rockwell C scale, and ball bearings are of course hard. This hardness allows them to rotate and not wear, at least for a while. The bearings surfaces of the hub cone and cup typically have a Rockwell C rating of 55 to 60. A steel ball bearing is likely to be over a Rockwell C of 60.

What are the grades of ball bearings?

Bearing balls are manufactured to a specific grade, which defines its geometric tolerances. The grades range from 2000 to 3, where the smaller the number the higher the precision. Grades are written “GXXXX”, i.e. grade 100 would be “G100”. Lower grades also have fewer defects, such as flats, pits, soft spots, and cuts.

Is the Earth smoother than a cue ball?

The Earth is smoother than a billiard ball. Let’s see. According to the World Pool-Billiard Association, a pool ball is 2.25 inches in diameter, and has a tolerance of +/- 0.005 inches. In other words, it must have no pits or bumps more than 0.005 inches in height. That’s pretty smooth.

Is Earth a sphere or spheroid?

The earth is not a sphere. The earth is an oblate spheroid with a diameter at the equator that is 43 km larger than at the poles, according to the National Oceanic and Atmospheric Administration.

Is the Earth smoother than a billiard ball?

You may have heard it has been said that if our planet were shrunk down to the size of a billiard ball, it would be smoother than it. In other words, the Earth is smoother than a billiard ball.

What if you shrank the Earth to the size of a ball?

If you shrank the Earth down to the size of a billiard ball, it would be smoother. I disagree with definition of smoothness used by Discovery Magazine. By that definition, medium sandpaper (grit particle size of 0.005 in) is also smooth, which doesn’t quite go with my definition of smoothness.

What would Earth feel like if it was as smooth?

SMOOTH EARTH: If shrunk to a few inches across, Earth would feel as smooth as a billiard-hall cue ball. Is Earth as smooth as a cue ball?

How deep is a billiard ball on the Earth?

Scaled down to the size of a billiard ball, Earth’s Mariana trench would be 49 μm deep. Let’s think it in another way: If a billiard ball was scaled up to Earth size, the difference between the highest peak and lowest point would be about just 223 meters (732 feet) at maximum. A billiard ball is way smoother than the Earth.