The industrial and construction sectors have literally hundreds of different types of screws and fasteners to select from; each type suited for a particular usage e.g. lubricated timber decking screws for quicker driving into outdoor decking, self-drilling screws for the convenience of not having to drill pilot holes and even screws that work specifically with the mechanical properties of plastics.
Before you can choose the best screw for a job you should consider the characteristics you desire in a screw such as:
* Does it need to be waterproof to avoid corrosion from moisture?
* Does the screw head need to be flush with material once it's screwed into place?
* Does the screw need to be protected from vandalism or unauthorised removal?
* Is the screw to be used in wood, metal or perhaps plastic?
* What length of screw is required?
For different types of material there tends to be a different type of screw. Take the following as examples:
* Wood screws – designed to perform best in all types of wood including hardwood, MDF and chipboard. Smaller screws have less chance of splitting wood, but if you're using larger screws and/or working near the end of a piece of wood then it's often safer to drill a pilot hole first.
* Floor screws – these will cope with the issue of different expansion rates so are best used for securing timber or chipboard to steel supports. Made by a process that ensures a hard exterior whilst retaining a tough, flexible core.
* Self-drilling screws – designed for convenience as only a screwdriver is required. These screws drill their own holes and form their own mating threads ensuring the best fit in a single attempt.
* Timber decking screws – specially designed to deal with outdoor conditions with durable, protective coatings.
* Frame anchor screws – designed for fixing window and door frames made from PVC-U, wood or aluminium directly to brickwork without the need for plugs or nylon anchors.
A general rule of thumb for determining an appropriate length of you should look for a screw length that will allow two-thirds of its length to be embedded into the material being fastened to. So, for example, if you're fastening a 1-inch thick piece of timber to a wooden post then you should be looking at embedding 2-inches of the screw into the post. That means you would require a screw length of 3-inches.
All good screw suppliers will be able to advise on the appropriate screws for your task. The important thing is to appreciate that not all screws are the same and that using the right screw can mean a secure installation, whilst the wrong screw can mean in an accident waiting to happen.
