Are you using the right screw for the job?

Do you know your Phillips from your Pozidrive? Or the difference between a coach screw and a carriage bolt?

Screws, nuts and bolts come in a mind-boggling array of names, shapes and sizes which can be a cause of confusion. However, we’re here to point you in the right direction with our quick guide to the most commonly used, and frequently misinterpreted, fixings products.

1. The Twin-Threaded Wood Screw

This humble all-purpose wood screw is the staple of any DIY or tradesperson’s tool box as it’s suitable for most timbers and applications. Fully threaded (with twin spirals down the length of the screw for greater grip and quicker installation), it can be used with a red or brown plastic wall plug into masonry.

2. Single-Thread Chipboard Screw

As the name suggests, this screw is ideal for chipboard or timber applications where you need to secure materials that aren’t too heavy. It can be screwed directly into wood.

3. Hex Set Screw

This product is one that often causes confusion. Commonly referred to as a ‘bolt’ by customers, when questioned further most people are actually describing the hex set screw. These fully threaded screws aren’t tapered like wood ones and can be used to fasten wood and metal together by screwing a nut onto the opposite end.

4. Carriage Bolt

Often mistaken for a coach screw – the carriage bolt has a cup head with a square hidden underneath the head for greater grip into the material being fixed. The hexagon nut can then be threaded onto the bolt from the other end and tightened.

5. Coach Screw

With a sharp end, coach screws aren’t designed to be accessed from the other side with a nut, unlike the carriage bolt. These screws can be driven in with a socket driver or impact wrench for heavier timber installations, and for fixing items to timber.

6. Screw head names

To add to the confusion, screw heads come in an assortment of designs for different purposes and tools. Most of us are familiar with the ‘slotted’ and ‘cross’ head, but how many others can you name?

  • Slotted head: (single line) a less common screw head mostly manufactured in brass and found in old furniture
  • Phillips: (cross head) normally found on a dry wall screw
  • Pozidrive: (cross head with a second cross) good for wood and timber
  • Torx: a six-pointed star commonly used for concrete applications
  • Tamper-resistant Torx: a small pin in the centre means a standard screwdriver can’t unscrew it. Ideal for construction projects that require added security
  • Hex or ‘Allen’: the hexagon head is used with an Allen or Hex key

When it comes to security screws and bolts, the head design relates to the level of strength required, rather than the application. Here at Fixings and Powertools Center, we have access to Hafren security fasteners, each with a security rating from one to five – from entry level security to maximum strength. For more details visit the product page of Hafren’s website.

Two screws about to revolutionise the industry include the concrete and cutter screws. The concrete screw is ideal for concrete and brickwork, and won’t expand or damage the brick when driven in. The cutter screw has a unique self-countersinking head with ribs and tucks on the underside, which channel into the surface without having to drill a countersink separately.

Still unsure which screw or bolt you need for your project? Come in and talk to our team – they’ll be more than happy to point you in the right direction.


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