by Alyaa El-Kafrawy

Created on: December 03, 2009

Introduction

Screws, bolts and nuts

What are they?

Well, basically they are fasteners! They could be used as a very good way of connecting stuff together and they are highly recommended to use instead of other adhesive solutions whenever it is possible. Why? Because they are easily mounted, adjusted or removed which will make things more easily installed and stored as they could easily be assembled and disconnected into small pieces.

A quick description for those who know nothing about those terms would be:

Screws and bolts are basically a cylinder that may or may not have threads on, the threads may cover the whole cylinder or there might be a part not threaded. The most obvious difference between screws and bolts is as the name implies; a screw has a head that could be fastened or loosened with a screwdriver while the bolt doesn't.

Nuts are more like a cylinder that is very short compared to its diameter and is hollowed. Its hollow part is internally threaded in order to mesh on the bolt/screw.

They all come with variety of shapes and sizes to fit all the different purposes they might be used for.

They are mainly defined by their diameter and length. They are among the standard parts that people can buy directly (they are not specially made).

The head of the screw or bolt comes in variety of shapes; they could be flathead, crosshead, flange, lag bolts, hex head, plow or others.

They could be made of zinc, aluminum, stainless steel, bronze, galvanized or steel. They come with different grades and range from fine to coarse.

In order to describe a screw or bolt according to the DIN standard (Deutsches Institut fur Normung: The German institute for standardization) for example we say M10; which means a screw that has the following properties:

Screw Diameter 10 mm

Core Diameter 7.92 mm

Length of thread 22 mm

That's in addition to lots of other specifications that you can get easily from a standard table. Each standard of course has its own notations and specifications that you can find in their newsletter or others.

Of course a regular buyer doesn't need to know all this information in order to buy a bolt/screw/nut. All you need to know is what you are using it for and what is the diameter that you require and of course whether or not they are threaded.

Learn more about this author, Alyaa El-Kafrawy.
Click here to send this author comments or questions.