Difference Between Bolt and Screw

Bolt vs Screw

Fasteners are devices that are used to hold or join objects together. They are very useful in closing sides or openings of everyday things that are being used by man such as envelopes, bags, boxes, machinery, and containers. In woodwork and metalwork, they are even more useful, and they come in the form of clips, ropes, cables, chains, wires, hinges, clamps, screws, and bolts.

A screw is defined as a type of fastener that has a threaded shank and a slotted head. It is tightened by employing a torque to its head and threading it into the materials that are to be joined and held together. The materials compress the screw and hold it tight. Rotating the screw clockwise will tighten it.

There are several types of screws that are being used today. Some of them are: concrete screw, board screw, dowel screw, drywall screw, mirror screw, wood screw, sheet metal screw, lag screw, and self-tapping screw.
A bolt, on the other hand, is also a type of fastener that has a threaded head or pin at one end which is inserted into a hole and secured by a nut. It holds and compresses materials together, and it sometimes has a plain shank. Unlike a screw, a bolt does not need to be turned in order to tighten it.

Some types of bolts are: carriage bolt, plow bolt, track bolt, tension control bolt, hex bolt, eye bolt, elevator bolt, and anchor bolt. Bolts that have heads can be used as screws. Some screws are also used as bolts.
Their most distinct difference is that screws need torque to be applied to its head to fasten it into the material while a bolt always needs a nut wherein the torque is applied. The bolt is held still while it is inserted into an existing hole in the material.
When being used, bolts do not need to be turned like screws do. In applying or removing screws, they need to be turned so that they will hold the materials well. Screws are also smaller than bolts.

Summary:

1.A screw is a type of fastening device that has a slotted head and a threaded shank while a bolt is a fastening device that has a pin or head at one end with a threaded or unthreaded shank.
2.To tighten a screw, torque is applied to its head, and it is turned in order to thread it to the materials that are to be joined. To tighten and secure a bolt, a nut is needed where the torque is applied.
3.While a screw is turned when being used and tightened, a bolt is held still.
4.A bolt is used to join together materials that already have holes while a screw is used in joining materials that do not have existing holes.
5.There are screws that can be used as bolts, and there are also bolts that can be used as screws.
6.A screw is usually smaller than a bolt.