Is a hex bolt the same as an Allen bolt?

A hex bolt and an Allen bolt are not exactly the same, but they are related.

A hex bolt, also known as a hex head bolt, is a type of fastener that has a six-sided head, typically with a threaded shaft that is inserted through a hole and tightened with a nut. The hex head is usually turned with a wrench or pliers.

An Allen bolt, on the other hand, is a specific type of hex bolt that has a hexagonal socket in its head, which allows it to be turned with an Allen wrench (also known as a hex key). Allen bolts are also known as socket head bolts or Allen head bolts.

So while all Allen bolts are hex bolts, not all hex bolts are Allen bolts.