• Pan head with a wide flat bearing face for extra clamping over thin sheet metal.
• Pozi PZ2 recess grips the bit, so you get less cam-out on the driver.
• 60 degree self-tapping thread cuts its own thread in a pre-drilled pilot hole.
• Fully threaded from head to point for a firm hold along the whole fixing.
• AB point starts fast once the pilot is drilled.
• Carbon steel with a Zinc & Clear Cr3 finish (trivalent chromium), silver in colour.
• Corrosion rating 1, so keep them to interior, dry, low-humidity work.
• Made to BS 4174:1972.
• Twelve sizes from 4.2mm diameter upwards.

• Stitching two sheets of thin metal together, metal to metal.
• Fixing brackets, trims, flashings and panels back to steel.
• Interior metalwork such as ducting, trunking and casings.
• Trade and DIY metal fixing where you can pre-drill a pilot hole.

A quick note on material. TIMCO advise against zinc plated carbon steel screws going into aluminium, as it can set off a bi-metallic reaction. Pick a different fixing for aluminium.

• Brand: TIMCO
• Material: A2 (304) stainless steel
• Finish: Self-colour stainless
• Head type: Countersunk
• Recess: Pozi (PZ1)
• Thread: 60 degree self-tapping, fully threaded
• Point: AB point
• Substrate: Metal, thin sheet
• Corrosion: High (interior and exterior)
• Installation: Pre-drilled pilot hole required
• Standard: BS 4174
• Pack: Box

Are these self-tapping or self-drilling screws?

Self-tapping. The screw cuts its own thread as it goes in, but it will not drill its own hole. That is the difference. A self-drilling screw has a drill-point tip and bores its own hole. These have an AB point, so you drill a pilot first, then drive the screw and let it tap the thread.

Do I need to pre-drill a pilot hole?

Yes. These are self-tapping, so a pilot hole is needed. Drive one into steel or thick sheet without a pilot and you risk snapping the screw or cracking the material. Drill the pilot, then fix.

What size pilot hole should I drill?

As a rule of thumb, size the pilot to roughly the screw's core (root) diameter, which is the solid centre without the thread. Go a touch smaller in thin or soft sheet so the thread bites, and a touch larger in thick or hard steel so it drives without straining. Every job is a bit different, so test on an offcut of the same material before you commit.

What is an AB point?

It is the tip type on the screw. An AB point is a sharp, gimlet-style point that starts quickly and finds the pilot hole with less wander. It is a common point for self-tapping screws going into sheet metal and thinner sections.

Why choose a pan head over a countersunk one?

A pan head sits on top of the surface with a flat, wide underside. That wide face spreads the load and clamps thin sheet without pulling through. A countersunk head sinks flush, which is better when you need a smooth surface. For stitching metal you usually want the clamping of a pan head.

Can I use these outside or into aluminium?

Keep them to interior, dry work. The corrosion rating is 1, so they are not meant for damp or exposed conditions. And avoid aluminium. TIMCO advise against zinc plated carbon steel in aluminium because of the bi-metallic reaction it can cause.