Nails, screws & wall plugs buying guide
Make sure you use the right fixing
Clout nails, lost-head nails, coach bolts, security screws, hammer-in plugs - the world of nails, screws and wall plugs can be daunting, so if you're going to do the job, make sure you use the right fixing.
Steel nails come in all shapes and sizes. Outdoors, always use zinc-plated galvanised nails - they help to delay rusting.
Clout nail
Used for fixing slates and window sash cords.
Cut floor brad
Has a rectangular cross-section and is used to fix floorboards to joists.
Felt nail/large-head clout nail
Shorter than the clout nail, it's used for attaching roofing felt.
Lost-head nail
Round nail that can be punched below the surface with a pin punch.
Masonry nail
Grips well in bricks and breeze blocks and is used for fixing wood to masonry.
Oval wire nail
Oval shape helps to prevent wood from splitting as it's hammered in.
Panel pin
Small, slim nail that's easily punched in and used for attaching, mouldings, joinery and general carpentry.
Plain-head wire nail
General-purpose round nail (take care - it can sometimes cause wood to split).
Plasterboard nail
Its jagged shank helps it to grip plasterboard.
Ring shank nail
Round nail with rings around its shank to make the fixing more secure. Use for tasks such as laying sub-floors and pinning exterior trim where the nail is unlikely to ever need to be removed.
Screws are usually made of mild steel, but hardened steel, stainless steel, solid brass and steel plated with chromium or brass are also available, as are galvanised rust-proof screws for outdoor use.
Anatomy of a screw
A screw has a head, a shank and a thread. Its length is measured from the pointed tip of the thread to the part of the head lying flush with the surface it's screwed into. The gauge is the diameter of the shank. Raised-head screws have heads that sit above the surface, countersunk screws have heads that are flush with or sink below the surface. Screws can have slotted or crossed heads - cross-headed screws being easier to drive in than slot-headed ones, especially with a power screwdriver.
Screw gauges
The imperial system of screw gauges ranked shank diameter as a number from 1 to 20 - the higher the gauge, the bigger the screw. The metric equivalents are not nearly so user-friendly, but this is how screws are now increasingly sold. Use this handy table as a guide:
| Gauge | Clearance hole | Pilot hole | |
|---|---|---|---|
| Metric | Imperial | ||
| 2mm | 2 | 2.5mm | 1.6mm |
| 2.5mm | 3 | 3mm | 1.6mm |
| 3mm | 4 | 3.5mm | 2mm |
| 3.5mm | 6 | 4mm | 2mm |
| 4mm | 8 | 5mm | 2.5mm |
| 5mm | 10 | 5.75mm | 3.5mm |
| 5.5mm | 12 | 6.5mm | 3.5mm |
| 6.5mm | 14 | 6.5mm | 4mm |
Types of screw
Carcass screw
Has a thick shank and a coarse thread, which can be useful for securing chipboard.
Chipboard screw
A deep thread extends right up to the head, making it good for wood as well as chipboard.
Coach bolt (cup square bolt)
A square neck under a domed head locks into the wood as the nut is tightened.
Coach screw
Has a square or hexagonal head that's driven in with a spanner. Gives a very strong, heavy-duty fixing.
Countersunk woodscrew
This traditional unhardened woodscrew has a single thread, and needs a pilot hole and shank-clearance hole to be drilled before it's fitted.
Dry wall screw
A twin-threaded screw used for fixing plasterboard or fibreboard to timber studs.
Hardened-steel woodscrew
Double threads make for fast insertion, with no need for a pilot hole if screwing into softwood.
Masonry screw
A strong screw that can be driven into masonry without using a wall plug.
Raised-head woodscrew
Used for decorative hardware fittings, this screw is countersunk to the rim of the head.
Round-head woodscrew
Used for fitting decorative door furniture.
Security screw
The shape of the countersunk head prevents the screw being removed once it's in place.
Self-tapping screw
Cuts its own thread in thin sheet metal and plastic.
A normal screw won't stay in masonry without a wall plug. The wall plug expands grip the sides of the hole when the screw is driven in, holding the screw securely in place. Ideal for use during a wide range of construction tasks, as well as for hanging shelves, pictures and mirrors around your home.
Moulded plastic wall plugs are produced on plastic 'trees', with the size of drill bit printed on the tree. Some manufacturers make different-sized wall plugs in different colours - but take care, as colours are not standard across all brands.
Hammer-in plugs
These alternatives to wall plugs and screws are good for fixing timber battens to masonry. One type has a wall plug with a ready-fitted screw. It's inserted into a drilled hole with a hammer, then driven home with the screw. There's also a version of this designed for plasterboard. The other type has a flanged expansion sleeve fitted with a masonry nail.
Moulded plastic wall plugs
These have a split end and can be bought to take a range of screw lengths and gauges.
Straight plastic plugs
These are tubes with ribs running lengthways. They take the screw thread only, so they have to be cut shorter than the depth of the hole.
