Buying screws, wall plugs and basic fixings

Understanding Basic Fixings

When setting up a home toolkit, the sheer variety of screws, plugs, and anchors available at the hardware store can be overwhelming. Buying the right basic fixings ensures you are prepared for common jobs like hanging pictures, assembling flat-pack furniture, or securing brackets.

1. Wood Screws

Modern wood screws are usually countersunk and feature a cross-head (like Phillips or Pozidriv) or Torx (star) drive.

• Twin-thread vs. Single-thread: Single-thread screws drive in faster and hold better in modern particle boards and MDF.
• Finish: Use zinc-plated screws for indoor use. For outdoor or damp environments, always use stainless steel or specially coated decking screws to prevent rust.

2. Wall Plugs (Rawlplugs)

A wall plug expands when a screw is driven into it, creating a tight friction fit in solid masonry or brickwork.

• Colour Coding: Plugs are often colour-coded by size. In the UK, the most common sizes for general household use are Red (for 6mm drill bits, used with lightweight items) and Brown (for 7mm drill bits, used for heavier items like shelves).
• Matching Drill Bits: It is critical to use the exact drill bit size specified on the plug packaging. A hole that is too large will cause the plug to spin freely without gripping.

3. Hollow Wall Anchors (Plasterboard/Drywall)

Standard wall plugs do not work well in hollow plasterboard walls because they have nothing solid to expand against.

• Self-drilling Anchors: These feature large, aggressive threads that bite into the plasterboard. They are great for medium loads like mirrors.
• Toggle Bolts (Spring Toggles): These feature wings that spring open behind the hollow wall. They provide the strongest hold for plasterboard but require a larger initial hole.

Buying Strategy: Assortment Boxes

For beginners, buying an assortment box of screws and matched wall plugs is often the most cost-effective way to start.

• Check the Quality: Very cheap assortment boxes often contain brittle screws that snap under pressure or heads that strip easily. Look for trade-quality brands (like Fischer or Spax).
• What to Keep on Hand: A box containing 3.5mm, 4.0mm, and 5.0mm diameter screws in lengths ranging from 25mm to 50mm will cover 90% of basic household tasks.

Common Mistakes

• Using the Wrong Screwdriver Bit: Using a Phillips bit in a Pozidriv screw will cause the bit to slip (cam-out), stripping the screw head.
• Over-tightening: In soft materials like plasterboard or MDF, overtightening the screw can destroy the thread it just cut, resulting in a loose fixing.
• Wrong Plug for the Wall: Using a standard masonry plug in a hollow plasterboard wall is a recipe for failure.

Safety Note

Always verify what is behind a wall before drilling. Use a pipe and wire detector to ensure you are not drilling into live electrical cables or water pipes. Do not use standard wall plugs for safety-critical overhead loads (like heavy ceiling fans).