A screw that splits the wood, a head that strips before it is even tight, a fixing that works loose in a week, or a rusty streak bleeding down a bathroom wall. Every one of these is usually the same mistake: the wrong screw for the job.
There is no single best screw, only the right screw for a given material, load and setting. Once you understand the handful of things that separate one type from another, the wall of boxes at the hardware shop stops being confusing and starts making sense. This guide decodes the main types of screws, wood, chipboard, drywall, self-tapping and machine screws, and shows you how to read heads, drives, coatings and sizes so you pick correctly every time.
It is part of our wider fasteners and fixings guide. Here we focus purely on screws.
The four things that define a screw
Every screw choice comes down to four questions. Answer these and you have chosen correctly.
- What is it going into? Wood, engineered board, thin metal, or a threaded hole. This decides the screw type more than anything else.
- What head shape do you need? Flush and hidden, or standing proud to clamp something down.
- What drive will you use? Philips, Pozi, slotted or Torx, which affects how much grip your driver gets and how easily the head strips.
- Where will it live? Dry indoor use, or damp, wet or outdoor conditions, which decides the coating or metal.
Keep these four in mind as we go through each screw type below.
Wood screws
The classic all-rounder for timber, plywood and general carpentry. Wood screws have a coarse thread that bites into timber and a smooth shank near the head that lets two pieces of wood pull tightly together. KTC stocks a wide spread of wood screws, mostly countersunk Philips heads, in chrome, zinc and stainless, across the common gauges and lengths.
Best for
- Furniture, frames, doors and general woodwork
- Fixing hinges, brackets and fittings into timber
- Joining timber to timber where you want a clean, flush finish
Tip
In hardwood or near the end of a plank, drill a small pilot hole first. It stops the wood splitting and makes the screw much easier to drive straight.
Chipboard and particle-board screws
Engineered boards like chipboard, particle board and MDF crumble easily, so they need a screw made for them. Chipboard screws have a sharper, deeper thread that grips the loose material firmly and a design that reduces splitting. They are the backbone of modular furniture and modern interior work. KTC carries chipboard screws in the popular sizes, from shorter screws for thin panels up to longer ones for thicker sections.
Best for
- Flat-pack and modular furniture
- MDF, particle board and chipboard assemblies
- Kitchen carcasses, wardrobes and interior joinery
Drywall and gypsum board screws
These are the black bugle-head screws used for false ceilings and gypsum-board partitions. The bugle head sinks neatly into the board without tearing the paper face, and the sharp thread pulls the board tight to the frame behind it. This is one of KTC’s deepest lines, with a full ladder of sizes from small 3.5 mm screws for thin single-board work up to longer 4.2 mm screws for double-board and thicker builds, and stocked from many trusted makers.
Fine thread vs coarse thread, the key choice
- Fine-thread drywall screws are made to bite into metal (GI) studs, the framing used in most modern partitions and ceilings.
- Coarse-thread drywall screws grip wood battens and timber framing.
Pick the length so the screw passes fully through the board and grips the frame, without driving so deep that it breaks the paper and loses its hold. If you are boarding a whole ceiling or partition, buy by the box to save money.
Self-drilling and self-tapping (SDS) screws
When you are fixing into thin sheet metal or metal profiles, a self-drilling screw saves a step. Its drill-point tip makes its own hole and cuts its own thread as it goes, so there is no separate pilot-drilling in many cases. Self-tapping screws are similar but usually need a small pre-drilled hole, after which they cut their own thread. KTC stocks a good range of SDS and self-drilling screws, including truss-head and countersunk types in common sizes.
Best for
- Fixing GI sheet, roofing sheet and metal profiles
- Ducting, trunking and light steel fabrication
- Attaching hardware to thin metal without tapping a thread first
Machine screws
Unlike the screws above, a machine screw does not cut its own thread in the base material. It has a straight, uniform thread that runs into a pre-tapped hole or into a nut, exactly like a small bolt. Machine screws are used in fittings, panels, appliances, electrical work and assemblies where the mating thread already exists. KTC stocks machine screws in steel and brass across common sizes and head types.
Best for
- Electrical fittings, switch plates and panels
- Machinery and equipment assemblies with tapped holes
- Anywhere a screw runs into a nut rather than into the material
When a machine screw runs into a nut, you are really building a bolted joint, so see our guide to nuts, bolts and washers for grades and washers.
Heads, drives and coatings
Beyond the screw type, three details finish the choice.
Head shapes
- Countersunk (CSK): sits flush with the surface for a clean finish. The most common head for wood and general work.
- Pan and truss: sit slightly proud with a broad bearing surface, good for clamping down thin materials, brackets and sheet.
- Dome and round: a rounded decorative head where appearance matters.
Drive types
- Philips: the everyday cross drive, simple and widely used.
- Pozi: a cross drive with extra grip that resists slipping.
- Torx (star) and hex: give the most grip and are hardest to strip, favoured for heavy and repeated driving.
The right driver bit matters as much as the screw. A worn or wrong-size bit is the fastest way to strip a head. KTC stocks driver bits, including the Taparia range, to match.
Coatings and materials
- Zinc and chrome plated: for dry, indoor work. Economical and clean-looking.
- Black phosphate: the standard finish on drywall screws.
- Stainless steel: for bathrooms, kitchens, exteriors and anything exposed to our Tricity monsoon, where a plated screw would rust and stain.
- Brass: corrosion resistant with a finished look, common in fittings and decorative work.
How to read a screw size
Screw sizes are usually written as two numbers, for example 8 x 50. The first is the gauge or diameter of the screw, and the second is the length in millimetres. So an 8 x 50 screw is roughly 8 units thick and 50 mm long. As a rule, choose a length that gives a firm grip in the base material, and a diameter suited to the load, thicker for heavier work, finer for delicate materials that might split. If you are fixing into a wall plug, the screw is matched to the plug rather than chosen on its own.
Fixing into masonry rather than wood or metal? You will need a wall plug or anchor. See our guide to the right wall plug for concrete, brick and drywall.
Quick reference: which screw for which job
- Timber, furniture, general carpentry: wood screw, countersunk.
- Chipboard, MDF, modular furniture: chipboard screw.
- False ceiling or gypsum partition: drywall screw, fine thread into metal studs, coarse into wood.
- Sheet metal, roofing, ducting: self-drilling or self-tapping (SDS) screw.
- Electrical fittings and tapped assemblies: machine screw.
- Bathrooms, kitchens, outdoors: stainless steel, whatever the type.
- Into a concrete or brick wall: a wall plug plus the matching screw, not a screw alone.
Frequently asked questions
What is the difference between a wood screw and a machine screw?
A wood screw has a coarse thread that cuts its own grip into timber. A machine screw has a uniform thread that runs into a pre-tapped hole or a nut, and does not cut into the base material itself.
What screw should I use for a gypsum board false ceiling?
Use drywall screws. Choose fine-thread screws for metal (GI) studs and coarse-thread for wood framing, in a length that grips the frame without over-driving through the board face.
Which screws are best for a bathroom or outdoor use?
Stainless steel. Plated zinc or chrome screws can rust in damp and wet settings and leave stains, so stainless is worth it wherever there is moisture or exposure to the weather.
Do I need a self-drilling screw for metal?
For thin sheet metal a self-drilling screw is ideal because it makes its own hole. For thicker metal you may pre-drill and use a self-tapping or machine screw into a tapped hole.
How do I stop screw heads from stripping?
Use the correct drive and a matching, undamaged driver bit, keep the driver pushed firmly into the head, and avoid over-driving. A worn bit or the wrong size is the usual cause.
Can I buy screws loose or only in boxes?
Many sizes are available by the piece as well as by the box, so you can pick up a handful for a small job or buy in bulk for a site. Ask us for the size and quantity you need.
The right screw, in stock and by the piece or the box
From a single stainless screw for a bathroom fitting to boxes of drywall screws for a whole ceiling, KTC Tools in Panchkula carries the full range of wood, chipboard, drywall, self-drilling and machine screws, along with the driver bits to match. Tell us the material and job and we will hand you the right screw. We serve the whole Tricity, Panchkula, Chandigarh and Mohali, and trade customers beyond it.
Visit: Shop No. 4, Street No. 2, Maheshpur, Sector 21, Budanpur, Panchkula, Haryana 134117
Call: 94175 65977 | WhatsApp: message us here
Trade or bulk order: get a quote. Browse more on our construction and hardware hub.
