Timco Premium Classic countersunk woodscrews in marine grade A4 stainless steel. Suitable for coastal, corrosive and outdoor environments. Available in a wide range of sizes from 3.0 x 12mm up to 6.0 x 150mm. Sold in boxes of 100 or 200.
Available options and pricing for Timco A4 Stainless Steel Countersunk Woodscrews, with quantity selectors and a running total
Size
QTY
SKU
Price
QTY
Total
6.0 x 100mm
100
60100CLASS-1
£24.16£28.99
—
3.5 x 20mm
200
35020CLASS-1
£4.85£5.82
—
3.0 x 15mm
200
30016CLASS-1
£3.70£4.44
—
3.5 x 25mm
200
35025CLASS-1
£5.23£6.28
—
3.5 x 30mm
200
35030CLASS-1
£6.15£7.38
—
4.0 x 25mm
200
40025CLASS-1
£6.07£7.28
—
4.0 x 30mm
200
40030CLASS-1
£6.91£8.29
—
4.0 x 35mm
200
40035CLASS-1
£7.78£9.34
—
4.0 x 40mm
200
40040CLASS-1
£8.44£10.13
—
4.0 x 50mm
200
40050CLASS-1
£10.20£12.24
—
4.0 x 60mm
200
40060CLASS-1
£12.56£15.07
—
4.0 x 70mm
200
40070CLASS-1
£14.73£17.68
—
5.0 x 30mm
200
50030CLASS-1
£11.02£13.22
—
5.0 x 40mm
200
50040CLASS-1
£13.54£16.25
—
5.0 x 50mm
200
50050CLASS-1
£15.77£18.92
—
5.0 x 60mm
200
50060CLASS-1
£18.39£22.07
—
5.0 x 70mm
200
50070CLASS-1
£21.32£25.58
—
5.0 x 80mm
200
50080CLASS-1
£24.28£29.14
—
5.0 x 100mm
100
50100CLASS-1
£17.62£21.14
—
6.0 x 80mm
200
60080CLASS-1
£35.34£42.41
—
6.0 x 130mm
100
60130CLASS-1
£32.68£39.22
—
6.0 x 150mm
100
60150CLASS-1
£37.66£45.19
—
Timco’s Premium Classic A4 stainless screws are the countersunk woodscrew you reach for when a standard zinc or yellow passivated screw simply won’t last. Made from marine grade A4 stainless steel, these screws are built for environments where corrosion is a real problem: coastal builds, external cladding, decking in exposed locations, green oak framing, and anywhere that moisture and salt are a permanent fixture. A4 stainless offers superior corrosion resistance compared to the more common A2 grade, making these screws the correct choice rather than just a cautious one.
The design is based on Timco’s Classic Multi-Purpose screw profile, which has proven itself across general timber fixing for years. The countersunk head sits flush or just below the surface, giving a clean finish without any protruding hardware. The double countersunk head reduces the risk of head shear during installation, which matters when you are driving screws into hardwoods or dense engineered boards at pace. Nobody wants to be picking out snapped heads on a job.
What Makes These A4 Stainless Screws Different
The thread geometry is worth understanding before you write these off as just another box of screws. The 40-degree deep single thread gives excellent pull-out resistance, meaning fixings stay put even in softer or more open-grained timbers. On lengths of 25mm and above, Timco has added a single slash cut to the tip. This reduces torque when driving close to the timber edge, cutting the risk of splitting without needing to pre-drill in most softwood applications.
Thread coverage is also well thought out. All screws up to and including 75mm are fully threaded along their entire length, giving maximum grip in thinner sections. On screws 80mm and above, the thread runs for 70mm from the tip, which is the practical zone where thread engagement matters most. This is consistent across the range and worth knowing when specifying screws for structural or load-bearing fixing applications.
Pre-drilling for Hardwood and Dense Sheet Materials
When fixing into hardwood, chipboard, MDF, or plastic, pre-drilling is recommended before driving these screws. This is not a weakness of the product, it is simply good practice with any countersunk screw going into a dense or brittle material. Pre-drilling also reduces the torque on the screw head, protecting both the fixing and the surface finish.
The range covers diameters from 3.0mm up to 6.0mm, with lengths running from 12mm to 150mm. Whether you are fixing small trim sections or driving long screws into structural timbers in a coastal environment, there is a size in this range to suit. Boxes come in quantities of 100 or 200, which keeps stock management straightforward on site. If you are working with green oak or other corrosive-reactive timbers, A4 stainless is not optional, it is the standard you need.
Pro Tip: When driving A4 stainless screws into hardwood, use a sharp pilot bit sized to the shank diameter rather than the thread, and apply consistent speed without high torque to avoid galling, which is where the thread seizes against the material and can snap the head clean off.
Timco A4 stainless steel countersunk screws are used across outdoor construction and joinery wherever corrosion resistance is a requirement rather than a preference. Typical applications include external timber cladding, decking, fencing, fascia and soffit boards, garden structures, marine boarding, and coastal building projects where salt air would quickly degrade a standard plated screw.
These screws are also the correct choice when fixing into green oak, sweet chestnut, and other tannin-rich hardwoods whose natural chemistry reacts with and corrodes zinc or steel fixings. Fabricators working with composite decking and uPVC trim boards also use A4 stainless to avoid staining or corrosion bleed on visible surfaces.
40 degree deep single thread for high pull-out resistance
Single slash tip on 25mm and above reduces splitting risk
Superior corrosion resistance versus A2 grade stainless
Not suitable for: Not suitable for use without pre-drilling in hardwood, dense chipboard, MDF, or plastic, as driving without a pilot hole risks splitting the material or shearing the screw head. These screws are not intended for masonry, concrete, or metal fixing applications.
For softwood applications, these screws can generally be driven directly without pre-drilling, though a pilot hole is always good practice when fixing close to a timber edge. For hardwoods, chipboard, MDF, and plastic, always pre-drill using a bit matched to the screw shank diameter before driving. Use a PZ2 driver bit for sizes up to 4.0mm and a PZ3 for larger diameters.
Set your driver torque to a moderate setting to avoid over-driving the countersunk head, particularly in softer timbers. Stainless steel screws are slightly more prone to galling than carbon steel, so steady, consistent speed is better than bursts of high torque. If a screw begins to resist mid-drive, back it out partially and clear any material from the thread before continuing.
Select the correct screw diameter and length for the timber thickness and load requirements of the fixing
For hardwood, chipboard, MDF, or plastic, drill a pilot hole using a bit matched to the screw shank diameter
For softwood, pilot drilling is optional but recommended when fixing within 20mm of a timber edge
Use a PZ2 bit for screws up to 4.0mm diameter and a PZ3 bit for 4.5mm and above
Set the driver to a medium torque setting to avoid over-driving and countersink damage
Drive at a steady, consistent speed to reduce the risk of galling on the stainless thread
Check the head sits flush or just below the surface once fully driven
What is the difference between A2 and A4 stainless steel screws?
A4 stainless steel contains molybdenum, which gives it significantly better resistance to chloride corrosion compared to A2. This makes A4 the correct grade for coastal locations, marine applications, and environments where salt air or standing water is present. A2 is adequate for general external use in less aggressive conditions, but for anything near the sea or in contact with corrosive timbers like green oak, A4 is the appropriate specification.
Do these screws need pre-drilling in hardwood?
Yes. When fixing into hardwood, dense chipboard, MDF, or plastic, pre-drilling is strongly recommended. Use a drill bit sized to the shank diameter of the screw, not the thread. This prevents splitting, reduces the torque required to drive the screw, and protects the head from shearing. In most softwoods you can drive directly, though a pilot hole is still good practice close to edges or in dry, brittle timber.
Why are screws 80mm and above only partially threaded?
On longer screws, a full thread from tip to head would cause the screw to act like a jack, potentially pulling the two timber sections apart rather than clamping them together. By running 70mm of thread from the tip and leaving a smooth shank for the remainder, the screw pulls the upper timber tight against the lower as it drives home. For screws up to 75mm, full threading provides maximum grip across shorter fixing depths where this clamping effect is not an issue.
Timco Premium Classic A4 stainless steel countersunk woodscrews are manufactured from grade A4 (316) stainless steel, which includes a molybdenum additive that resists pitting and crevice corrosion in chloride-rich environments. The Pozi countersunk head profile uses a double countersink to improve bearing area and reduce head shear stress during installation. The 40-degree thread angle provides high pull-out values in both softwood and engineered timber substrates. A single slash tip on lengths of 25mm and above assists material displacement during driving to lower splitting risk near board edges.
Brand
Timco
Grade
A4 (316) Marine Grade Stainless Steel
Head Type
Countersunk
Drive Type
Pozi
Thread Type
40 degree deep single thread
Tip
Single slash on 25mm and above
Thread Coverage
Fully threaded up to 75mm; 70mm thread on lengths 80mm and above
Available Diameters
3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm, 6.0mm
Available Lengths
12mm to 150mm
Box Quantities
100 or 200
Size
3.0 x 12mm, 3.0 x 20mm, 3.0 x 25mm, 3.0 x 30mm, 3.5 x 12mm, 3.5 x 20mm, 3.5 x 25mm, 3.5 x 30mm, 3.5 x 40mm, 3.5 x 50mm, 4.0 x 20mm, 4.0 x 25mm, 4.0 x 30mm, 4.0 x 35mm, 4.0 x 40mm, 4.0 x 45mm, 4.0 x 50mm, 4.0 x 60mm, 4.0 x 70mm, 4.5 x 20mm, 4.5 x 30mm, 4.5 x 40mm, 4.5 x 50mm, 4.5 x 60mm, 4.5 x 70mm, 4.5 x 80mm, 5.0 x 100mm, 5.0 x 25mm, 5.0 x 30mm, 5.0 x 40mm, 5.0 x 50mm, 5.0 x 60mm, 5.0 x 70mm, 5.0 x 80mm, 5.0 x 90mm, 6.0 x 100mm, 6.0 x 120mm, 6.0 x 130mm, 6.0 x 150mm, 6.0 x 40mm, 6.0 x 50mm, 6.0 x 60mm, 6.0 x 70mm, 6.0 x 80mm, 6.0 x 90mm, 3.0 x 15mm, 3.0 x 17mm, 3.5 x 15mm, 3.5 x 17mm, 3.5 x 35mm, 4.0 x 15mm, 4.0 x 17mm, 4.5 x 35mm, 4.5 x 45mm, 5.0 x 35mm, 5.0 x 45mm, 5.0 x 75mm
Box Quantity
100, 200
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