Metric vs. Standard Sockets

Socket wrenches never need repositioning, and can be used more efficiently than standard wrenches.

As any mechanic knows, sockets come in metric and U.S. standard versions. Metric sockets measure in millimeters, while standard sockets measure in fractions of an inch.

History

Throughout history there have been many different systems of measurement. People in different countries, and even different towns, used their own units. These were often based on the size of a ruler's foot or hand. England solved this problem by creating the Imperial system of measurement, which later evolved into the standard system. The French solved this problem by creating the metric system.

Geography

In most of the world, the metric system is used for sockets. The United States manufactures and uses sockets in the U.S. standard system.

Considerations

Mechanics in the United States work with cars and other machines built both in the U.S. and overseas. For this reason, they often need to buy two sets of sockets, one in metric and the other in standard.

Overlap

Though metric and standard sockets use different units of measurement, they overlap in some places. For instance, a 13 mm metric socket is interchangeable with a 1/2-inch standard socket.

References

• SOS Math: SAE to Metric Conversion
• France Property and Information: Imperial and USA Measurement Systems and History
• SAE International: An Abridged History of SAE
• Northern Michigan University: History of Measurement

Resources

• New Mexico State University: Origin of the Metric System