Types of Screws: A Practical Buying Guide
The head. The material. The fit.
A practical look at six screw families and the details to check before choosing.
A screw can be the right length and still be wrong for the job. The head might not fit the hinge, the thread might not match the fitting, or the finish might not suit the conditions.
Start with what you are fixing into and the fitting you are securing. Then check the diameter, length, head, drive and finish. Once those details are right, choose the pack quantity.
Here are six useful starting points from our range, followed by a size check you can use before ordering.
Wood screws and timber screws
For a timber repair, a workshop build or general joinery, start with the Woodscrews range. Check that the particular screw is intended for your timber or board and the job you have in mind.
A thin trim fixed to a thicker timber member and a hinge fixed into the edge of a cabinet panel need different checks. Record the thickness being fixed through and the depth available behind it. Follow the screw and fitting instructions for preparation, including any pilot hole requirements.
Countersunk or pan head: check how the screw should sit
Look at the fixing hole before choosing the head. It matters even when the diameter and length are the same.
Countersunk
A shaped recess for the screw head
Match the head to the recess in the fitting.
Pan head
A flat fixing face with space above it
Check that the raised head will not catch or obstruct another part.
The original head style
A missing screw from an existing fitting
Compare an intact screw from an equivalent fixing point, where available.
A countersunk head seats in a matching recess. A pan head has a rounded top that remains above the surface. For example, if the original screw sat flush in a hinge, a pan head is not a direct replacement just because the diameter matches. These are head-shape differences, not strength ratings. Head-style reference.
Compare two head styles from our range
The photographs show the head profiles and are not shown to the same scale. The prices below are for two different lengths; neither length is a recommendation for your job.
Double-countersunk woodscrews
Double-countersunk head. Check the head seat and choose the length your joint needs.
3.5mm × 12mm · Pack of 100
View this pack
Pan head woodscrews
Raised pan head. Check that the fitting has a suitable flat seat and room for the head.
3.5mm × 16mm · Pack of 100
View this packBlack screws and visible-finish screws
When screws will be visible against a black hinge, bracket or other fitting, the finish becomes part of the choice. Get the fixing details right first: a colour match does not establish that the screw suits the material or conditions.
Our black woodscrews, 5mm × 40mm are one example to compare. Check their head, dimensions and product details against your fitting before choosing a pack.
Replacing the bracket too? Compare the fixing holes on the new bracket before buying screws to match the old one. If it needs replacing, the Brackets range is a useful next step. There is no need to replace a sound fitting just to change the screw finish.
Decking and exterior screws
For decking boards or other outdoor timber jobs, use our Decking & Landscaping Screws range as a starting point.
Check the product's stated use, coating or material, and the installation instructions for the timber or decking system. Outdoor suitability cannot be judged from colour alone. The required length, head and preparation still depend on the joint.
Keep any specified fixing requirements from the decking or timber supplier when comparing alternatives.
Concrete screws and masonry screws
For a fixing into a wall, identify the base material first. Concrete, brick and block are not interchangeable specifications. Use the Masonry & Concrete Screws range to compare products whose instructions cover that material.
Before ordering, check:
- The permitted base material.
- The specified drill diameter and hole depth.
- The item thickness and required fixing depth.
- The head style and installation instructions.
Check whether the chosen product fixes directly into a prepared hole or is part of a screw-and-plug arrangement. For a plug fixing, the plug instructions need to cover both the wall material and the screw dimensions. Do not apply a timber screw-length rule to a masonry fixing.
Furniture screws and connector fixings
Flat-pack furniture and cabinet joints may use cam locks, cam dowels or connector bolts. Start by identifying the fitting already in the furniture, then compare its dimensions with the replacement.
Our 34mm cam lock dowel screw is one example. Length alone does not establish a match: the head, thread and mating cam also matter.
If the joint uses a cam and dowel, check both parts before ordering. You may only need to replace one. If both are missing or damaged, confirm the matching specifications before adding them to your basket.
Use the furniture connector guide to identify the fitting, then compare the options in Furniture Fixings.
Electrical socket screws
Our Electrical Socket Screws range includes M3.5 screws for socket and switch faceplates. Check the thread, required length, head and finish against the fitting.
The M3.5 silver socket screw, 50mm is one length to compare, not a default for every back box. A longer screw is not automatically the right answer to a loose faceplate.
This section is for identifying replacement screws. If the fitting is damaged or you are unsure what is needed, ask an electrician to check it.
Choose the size from the joint
Before choosing the length, measure the part the screw passes through and the depth available in the receiving material. Check the fitting instructions too. A thickness multiplier cannot cover every job.
Material and condition
The fixing must suit what is actually there. A larger screw does not solve every damaged fixing point.
Thickness of the first piece or fitting
This uses part of the screw's length before it reaches the receiving material.
Usable depth behind it
Check the available depth and where the screw point would finish.
Existing hole and head seat
These help determine the diameter and head style.
Instructions for the fitting and screw
These set any specific size, preparation and installation requirements.
Keep head, drive and diameter separate
The head is the shape that sits against or in the fitting. The drive is the recess that takes the screwdriver or bit. Phillips, Pozi and Torx are drive types; match the bit type and size to the product details. Fastener identification reference.
For the flat-topped countersunk screws shown above, measure the full length from the top of the head to the point. For pan head screws, measure from the underside of the head to the point. The head is excluded from the pan head length. Check the product drawing for other head styles. Measuring reference.
If your old measurements use inches or a screw gauge, our conversion reference can help interpret them. Check the converted size against the exact product specification before ordering.
Choose a pack for the work you have
Count the screws needed for the job, then compare the available pack quantities. For repeat work, compare the price per screw as well as the total pack price. Buying more only makes sense if it is a size and type you will use.
Check what is included with the fitting before adding extras. A bracket may have fixing requirements of its own, and a furniture connector may need a separately supplied mating part. Add the parts the assembly calls for, with their specifications checked.
Before you order
- Confirm the material and fitting the screw needs to suit.
- Check diameter, length, head and drive.
- Check the stated finish or material for the conditions.
- Follow any specified preparation and installation requirements.
- Count the screws and any separately required components.
- Confirm the selected variant, pack quantity and current price.
For timber work, compare sizes in our Multi-Purpose Woodscrews range. If you are still choosing the screw family, start with Screws & Timber Fixings.
Common screw-buying questions
What type of screw should I use for wood?
Start with the wood-screw family, then check the particular product for your timber or board, joint, head style and conditions. Keep any fixing specification supplied with the fitting.
What screws should I use outside?
Choose a product whose stated material or coating and intended use cover the conditions of the job. Compare the relevant exterior range, then check the product instructions rather than choosing by colour or length alone.
Can I use wood screws in masonry?
A suitable wood screw can be used with a compatible wall plug where the plug instructions allow it. That is a different arrangement from a concrete screw designed to fix directly into a prepared hole. Identify the wall material and follow the instructions for the chosen fixing system.