Classic Multi-Purpose Screws – PZ – Double Countersunk – Exterior – Black Organic

Name: Black Exterior Multi-Purpose Screws PZ | Insane Bulk Discounts
Brand: Classic
SKU: CLABK
Availability: InStock

From £1.33£1.60 EX VATINC VAT

Black organic coated multi-purpose woodscrews built for exterior use. Rated to over 1,000 hours salt spray resistance. Double countersunk head reduces shear risk. Sharp point only. Ideal for use with black ironmongery.

Size	Price	QTY
3.5 x 16mm	£1.33£1.60
3.5 x 25mm	£1.93£2.32
4.0 x 25mm	£2.35£2.82
4.0 x 30mm	£2.60£3.12
4.0 x 40mm	£3.26£3.91
5.0 x 30mm	£3.98£4.78
5.0 x 40mm	£5.21£6.25

Size

Clear

Credit Plans Available

Description

These Classic black exterior multi-purpose screws are built for jobs where a standard zinc screw simply won’t hold up. The black organic coating delivers over 1,000 hours of salt spray resistance, making them a solid choice for outdoor timber work, fencing, gates, decking frames, and anything paired with black ironmongery. They look right, and they last.

The double countersunk head is one of those design details that earns its keep on site. It reduces the likelihood of head shear during drive and helps the screw seat cleanly into the timber without the head proud of the surface. Less cam-out, cleaner finish, fewer snapped heads. Useful when you’re halfway through a run of 200 and don’t want to be drilling anything out.

What Sets These Black Exterior Screws Apart

The 40-degree deep single thread gives strong pull-out resistance in softwood and hardwood alike. That matters when the fixing is load-bearing or when the timber is going to move seasonally, which outdoor wood inevitably does. A sharp point means no pre-drilling on most timbers, which keeps the job moving.

The PZ drive is the standard on site for good reason. It gives a positive engagement and transfers torque efficiently without the slip you get from older slotted or crosshead drives. Use a PZ2 bit for the smaller sizes and a PZ2 or PZ3 for the 5.0mm range depending on your driver.

Available in a range of sizes from 3.0 x 12mm up to 5.0 x 40mm, there’s enough range here to cover most exterior fixing tasks without switching product. Sold in boxes of 200, so you’re not running out halfway through a gate installation either.

Pro Tip: When fixing into treated timber outdoors, pilot the last few millimetres on hardwoods to avoid splitting near the end grain, even with a sharp-pointed screw.

Applications

These black exterior multi-purpose screws are used across a wide range of outdoor timber applications. Common jobs include garden gate construction, close-board fencing, pergolas, decking subframes, external joinery, and outbuildings. Anywhere you're using black hinges, latches, or other black ironmongery, these screws keep the aesthetic consistent rather than leaving silver heads against black hardware.

They're also a practical choice for landscaping contractors and groundworkers fixing timber edging, raised beds, and outdoor structures where the fixing will be exposed to weather long term. The coating holds up without needing additional protection, which saves time and reduces maintenance callbacks.

Best For

Exterior timber fixing
Garden gates and fencing
Decking subframes
External joinery
Use with black ironmongery
Pergolas and outbuildings

Compatible Surfaces

Softwood
Hardwood
Treated timber
Sheet materials

Key Properties

Black organic coating
1,000+ hour salt spray resistance
Double countersunk head
40-degree deep single thread
High pull-out resistance
Sharp point
PZ drive

Not suitable for: Not suitable for use in direct contact with concrete, masonry, or steel fixings. Sharp point only, so not appropriate where a self-drilling or serrated point is required for harder materials.

Usage

Select the appropriate size for the timber thickness and load. As a general guide, the screw length should be at least twice the thickness of the top piece being fixed. For most exterior softwood work, a 4.0 x 40mm covers a lot of ground.

Drive with a PZ2 or PZ3 bit depending on screw size. Keep the driver speed moderate on hardwoods to avoid stripping the head. No pre-drilling is needed on most softwoods thanks to the sharp point, but pilot the last portion when fixing close to end grain or into dense hardwood to prevent splitting.

Select the correct screw length based on material thickness, aiming for at least twice the depth of the top piece
Mark fixing positions and check alignment before driving
Use a PZ2 bit for sizes up to 4.0mm and a PZ2 or PZ3 for 5.0mm screws
Drive at moderate speed, particularly in hardwood, to avoid cam-out or head damage
Allow the double countersunk head to seat flush without over-driving
Pre-drill close to end grain or in dense timber to prevent splitting

FAQs

Are these screws suitable for use with pressure-treated or tanalised timber?

Yes, the black organic coating is designed to resist corrosion in exterior conditions, including contact with treated timber. For highly acidic preservative treatments, check the treatment specification if in doubt, but these perform well in standard outdoor applications.

Why is it double countersunk and what difference does it actually make?

The double countersunk head has a secondary recess above the primary countersink. This helps the screw start its own countersink in the timber more cleanly and significantly reduces the risk of head shear under torque, which is a common frustration with standard single countersunk screws when driving at speed.

Technical Information

Classic multi-purpose screws feature a carbon steel construction with a black organic coating rated to over 1,000 hours salt spray resistance in accordance with standard corrosion testing. The 40-degree thread angle provides high pull-out resistance in both softwood and hardwood. The double countersunk head geometry reduces stress concentration during drive, lowering the risk of head shear. PZ drive configuration throughout the range.

Drive Type	Pozi (PZ)
Head Type	Double Countersunk
Coating	Black Organic
Salt Spray Resistance	1,000+ hours
Thread Type	40-degree deep single thread
Point Type	Sharp point
Available Sizes	3.0 x 12mm, 3.0 x 16mm, 3.0 x 20mm, 3.5 x 16mm, 3.5 x 25mm, 4.0 x 25mm, 4.0 x 30mm, 4.0 x 40mm, 5.0 x 30mm, 5.0 x 40mm
Box Quantity	200