Self-tapping, self-drilling and machine – Which screw for which job?
Posted by Jill Glen on 22nd Mar 2023
Choosing the right screws for the job is not easy even for the most experienced professionals. On Diamond’s online store, we have over 800 types of screws, and although it would make our lives so much easier, fixings and fasteners are not interchangeable! Mixing up types of screws can cause delays and, even worse, failures on site, so it’s important to pick the right type for the right job.
Self-tapping and Self-drilling
These are probably the two types we see people confuse most often, but sell-tapping and self-drilling screws are not the same. Both are ideal for working with metal and plastics, but it’s important to know the difference:
Self-Tapping Screws
Self-tapping screws make their own threads in the material. You can get self-tapping screws which will tap a thread into wood, metal, and even brickwork. However, these screws cannot drill their own hole and need a pilot hole to be drilled before you screw them into place.
Self-Drilling Screws
Self-drilling screws also tap their own thread, but they also have a drill bit shaped point and they do not require a pilot hole. This can speed up your process but it is only suitable for certain grades of metal and plastics.
Wood Screws
As you might guess, wood screws are made for use in wood, MDF and chipboard. They are inexpensive, very strong, and you often don’t need to drill a pilot hole due to their very sharp point.
Machine Screws
Machine screws are not screws that you put in with a machine, they are screws that usually go in a machine! They are used in electronics, cars, and other machinery and have a flat tip meaning they are only for use with pre-drilled holes. Some machine screws are secured with a nut and they come in a huge variety of styles and sizes.
Knowing which kind of screw is only the first stage. Next, you need to know the right screw for the material, the diameter you need, and how many you need! If you need help or advice, we have the staff on hand to help you. View our screws online here, or visit our trade counters to speak to one of our team.