Our simple guide to screws and bolts

There are so many varieties of screws and bolts that sorting through them all can be something of a headache. That said, we’re always up for a challenge, so we’ve put together this handy guide to everything with a thread.

Types of screws and bolts:

  1. Wood screws

Sharp-tipped screws for use in wood. Outdoor varieties include stainless steel, zinc-coated, and Japanned.

  1. Decking screws

For fastening outside decking. Covered in a waterproof coating to protect them from the weather.

  1. Coach screws

For fixing large, heavy pieces of structural wood. Masonry use requires a pre-drilled hole and a plug. They have a hex head that is turned with a socket or wrench.

  1. Carriage bolts

These bolts have a rounded head and a square anti-spin shoulder. Used in fastening timber, they’re turned with a socket or wrench.

  1. Drywall screws

Specially made to be used in plasterboard. These have a trumpet-shaped ‘bugle’ head that goes into the board without tearing up the exterior.

  1. Machine screws

Straight-shanked and shaped like a bolt. Slotted head is turned with a screwdriver. Pre-drill a hole to provide a strong fastening.

  1. Roofing bolts

Mushroom-headed bolts used for fixing roofing and guttering. Double slotted with a square nut.

  1. Self-tapping screws

These create their own thread as they are being driven. Often used for fixing metal. Stainless steel or zinc-plated self-tappers are recommended outdoors to prevent rusting.

  1. Tek screws

Drill point enables them to tap their own hole. Used in sheet metal and cladding. Usually hex-headed or Pozi-headed. Also available with a bonded washer to create a water-tight seal for outdoor applications.

  1. Hex bolts

Hex-headed bolts with a partial thread. A popular choice in construction and machinery. Tighten with a socket or wrench. Also available as fully-threaded hex set screws.

  1. Concrete screws

Self-tapping screws for concrete, brick, and masonry, they don’t require a wallplug. Hex-headed; use a socket driver or wrench to turn them.

  1. Blue concrete screws

These specially-treated concrete screws are resistant to corrosion, making them ideal for long-term outdoor use.

  1. Socket screws

The head contains an internal hex connection that is driven with a socket. They’re handy for when a lack of space makes screwing difficult.

  1. Security screws

Designed to stay put permanently, these non-reversible screws feature a special head that can only be turned clockwise.

  1. Mirror screws

These come with a chrome cap that covers the head once installed to provide an attractive finish. Used in mirrors and glass.

We stock a wide range of screws and bolts for all your fixing and fastening needs. If you have any more questions, our team is always happy to help, so get in touch at our Redhill store.

Choosing the right screw for the job: our easy-to-follow guide

We’re often asked about the right screws to use when fastening to certain materials. With so many options out there to choose from, knowing which one is right for the job can be a bit of a conundrum. That’s why we’ve put together this quick guide to help you find the best screw for the material you’re working with.

  1. Best screws for wood

This depends on whether the wood is used indoors or outdoors. Brass and stainless steel woodscrews are rustproof, making them ideal for outdoor use. Their non-corrosive properties also make them suitable for hardwoods like oak and chestnut, which contain acidic tannins.

Japanned screws have a black lacquered coating that also protects from weather, and can be used outdoors with wrought iron, or for when you want a dark screw head.

MDF and chipboard screws are for use with MDF and chipboard, funnily enough. They are designed to deliver maximum grip in fibrous wood materials, but extra retention can be gained by drilling a pilot hole before driving the screw in. MDF and chipboard are not for outdoor use.

For fastening outside decking, use specialised decking screws. These are covered in a waterproof coating to protect them from the weather.

  1. Best screws for plasterboard

Drywall screws are specially made to be used in plasterboard. These have a trumpet-shaped ‘bugle’ head that goes into the board without causing excess damage to the exterior.

  1. Best screws for metal

Use a self-tapping screw. These create their own thread as they are being driven, but need a pilot hole to give them a headstart. Drill one slightly narrower than the gauge of the screw. If used outdoors, go for stainless steel or zinc-plated self-tappers to prevent rusting.

  1. Best screws for plastic

When screwing into plastic or fiberglass, first drill a pilot hole. Although you can use self-tapping screws, screwing straight into the plastic without pre-drilling will tear a rough hole, which could lead to further damage.

Other screws available:

Mirror screw

A two-part screw used for mirrors or bath panels. Once the screw is in, a rounded chrome cap is screwed over the head for a neat, decorative appearance.

Coach screw

Used for fixing large, heavy pieces of structural wood, these require a pre-drilled hole the length of three-quarters of the screw. Coach screws have a hexagonal-shaped head that is turned using a spanner.

So, what materials can you screw directly into, and which need to be drilled first? Here’s a rundown of the most common ones.

  1. Screwing into brick

When fastening to brick, you need to consider the weight of the object you’re attaching. For light and medium weight attachments such as hanging basket brackets, a stainless steel screw driven into a plastic wall plug will do the job. For heavier objects, it’s advisable to insert a more heavy-duty anchor into the brick to create a stable fastening.

Start by drilling a pilot hole using a hammer drill and a masonry bit. Clear out any debris using a vacuum cleaner nozzle. Now add the wall plug or anchor. Wall plugs are made of flexible plastic and can be squeezed into the hole with just your fingers, but metal anchors usually require a hammer to install. Once the anchor is in, all that’s left is to add the screw.

  1. Screwing into mortar

Although mortar is less dense than brick, you still need to drill a pilot hole and add a wall plug or anchor before you can screw into it.

  1. Screwing into concrete

Once you’ve drilled a pilot hole using a hammer drill and masonry bit, add a wall plug or anchor, depending on the weight of the object you’re attaching. Alternatively, use a masonry screw to screw straight into the pilot hole. These sturdy self-tapping screws are resistant to corrosion and have a fierce thread to help them bore into stonework.

  1. Screwing into plasterboard

No pre-drilling necessary, but use a drywall screw.

We’re confident that no matter what the job, we can help you find the right screw to get it done. Our experts are on hand at our Redhill store to help with any questions, so just drop by or get in touch.

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.