What is the Difference Between a Bolt and a Screw?
Bolts and screws are both Building Fasteners that help to position objects and hold them together. Some say that bolts are screws but not all screws are bolts. There are not really hard set distinctions between bolts and screws but they do have a few specifications. Some examples of screws are Headcote Screws, Heavy Hex Screws and Hex Cap Screws, examples of bolts are Heavy Hex Bolts.
What are Screws?
If it has a head on one end it is a screw. The head is driven or turned with a screw driver or sometimes with a wrench. The diameter ranges vary to meet demands and needs of specific products. Screws are generally turned into an object, like a piece of wood, so the head needs to be bigger than the surface. This prevents the screw from being turned further than the length of the screw itself. There are a few exceptions. For example, set screws have smaller heads and have special uses. There are a few screws that are tightened counterclockwise but most of them are tightened by turning clockwise.
What are Bolts?
Bolts are screws that rotate into a matched nut to tighten it. Bolts have a bigger head than the shaft, with a few exceptions. Carriage bolts and J-bolts are among those exceptions. The shafts of bolts are not tapered, whereas many screws are tapered. The main difference between a bolt and a screw is that a typical screw can work on its own and a bolt requires a nut to secure it.
With the exception of the Machinery’s Handbook, which states, “A bolt is an externally threaded fastener designed for insertion through holes in assembled parts, and is normally intended to be tightened or released by torquing a nut. A screw is an externally threaded fastener capable of being inserted into holes in assembled parts, of mating with a preformed internal thread or forming its own thread, and of being tightened or released by torquing the head,” there are few places that attempt to define the difference between a screw and a bolt. The important thing to remember is that each has its own purpose and you should be careful to use the right screw or bolt for the project that you are working on. You should find out what the bolt or screw is made of and what strength it is capable of before you choose a bolt or nut for your project. Screws and bolts do many of the same things but there are many types and you should consider what you need it to do before choosing one or the other.
