ABR Self-Drilling Dome Head Screw

Pan head (dome head) self-drilling screw that pierces and threads into steel and aluminium profiles in a single action — no pre-punching, no pre-drilling. Made of C1035 steel with a cold-galvanized coating, PH2/PH3 bit, and approved pull-out and shear data for safe structural design.

Self-drilling — no pre-drillSteel & aluminium profiles5 diameters ST3.5–ST5.5Approved pull-out & shear dataC1035 cold-galvanizedPH2 / PH3 bit

The Adit self-drilling screw family

Choose the right self-drilling screw for your head profile, bit and environment.

ABRDome / pan head · PH bit · steel & aluminium ABPCountersunk flat head · PH / Torx bit PS3 / PSLSandwich-panel screws · EPDM washer

Approved technical data — connection to steel & aluminium profile

The following data forms the basis for safe structural design. All values are in kN per single screw and include characteristic failure loads (Nrk/Vrk), design loads (Nrd/Vrd) and recommended service loads (Nrec/Vrec). For engineering design an appropriate safety factor must be applied, and the engineer must also verify the tear-out capacity of the profile itself.

ST 4.8 — connection to steel profile

Load parameter (kN)	Steel thickness 2 mm	Steel thickness 3 mm	Steel thickness 4 mm
Failure load — pull-out (Nrk)	5.7	7.1	7.1
Failure load — shear (Vrk)	3.6	3.6	3.6
Design load — pull-out (Nrd)	2.6	3.9	5.2
Design load — shear (Vrd)	2.7	2.7	2.7
Recommended load — pull-out (Nrec)	1.9	2.8	3.7
Service load — shear (Vrec)	2.0	2.0	2.0

ST 5.5 — connection to steel profile

Load parameter (kN)	Steel thickness 2 mm	Steel thickness 3.5 mm	Steel thickness 5 mm
Failure load — pull-out (Nrk)	5.4	8.7	9.6
Failure load — shear (Vrk)	4.8	4.8	4.8
Design load — pull-out (Nrd)	2.5	4.0	4.8
Design load — shear (Vrd)	3.7	3.7	3.7
Recommended load — pull-out (Nrec)	1.8	2.9	3.4
Service load — shear (Vrec)	2.6	2.6	2.6

ST 4.8 — connection to aluminium profile

Load parameter (kN)	Aluminium thickness 2 mm	Aluminium thickness 3 mm	Aluminium thickness 4 mm
Failure load — pull-out (Nrk)	2.9	4.6	6.4
Failure load — shear (Vrk)	3.6	3.6	3.6
Design load — pull-out (Nrd)	1.3	2.1	2.9
Design load — shear (Vrd)	2.7	2.7	2.7
Recommended load — pull-out (Nrec)	1.0	1.5	2.1
Service load — shear (Vrec)	2.0	2.0	2.0

Note: the shear capacity does not account for tear-out of the profile (steel or aluminium). The engineer must check the profile’s tear-out capacity to determine the final shear capacity. Using steel screws to fasten aluminium can cause galvanic corrosion.

Geometry and dimensions

Adit’s ABR self-drilling dome head screw series offers dimensions to match every steel thickness and drilling requirement:

Screw diameter	Head diameter (dk) mm	Head thickness (k) mm	Bit	Recommended steel thickness (mm)	Drilling speed in steel (rpm)	Max installation torque (Nm)
ST 3.5	6.9	2.6	PH2	0.70 – 2.25	1800 – 2500	2.8
ST 3.9	7.5	2.8	PH2	0.70 – 2.25	1800 – 2500	3.8
ST 4.2	8.2	3.05	PH2	1.75 – 3.00	1000 – 1800	4.7
ST 4.8	9.5	3.55	PH2	1.75 – 4.40	1800 – 2500	6.9
ST 5.5	10.8	3.95	PH3	1.75 – 5.25	1000 – 1800	10.4

What is a self-drilling dome head screw (pan head self-drilling screw)?

A self-drilling dome head screw, also known as a pan head self-drilling screw (Self-Drilling Screw Dome Head), is an engineered fastening solution that combines a drilling tip (drill flute) at its point with a round, flat dome profile at its head (Pan Head / Dome Head). This construction lets the screw pierce the base material and thread into it in one continuous action — with no need for pre-punching or pre-drilling a hole.

Unlike a standard self-tapping screw that requires a pre-formed hole, the ABR self-drilling dome head screw eliminates an entire installation step. The dome head provides a wide bearing surface over the fastened material, distributing the load and preventing it from sinking into the material. The result: minimal working time, fewer tools required, and a significantly lower total installation cost.

The ABR self-drilling dome head screw is suited to applications such as: connecting light gauge steel profiles, assembling metal panels and cladding, drywall construction, framing, roofing, and a wide range of structural, cladding and industrial applications where a discreet, flat screw head is required.

The advantages of the ABR self-drilling dome head screw — not every pan head self-drilling screw is the same

Approved technical data: precise pull-out and shear values for every diameter and profile thickness (enabling safe engineering design).
Aesthetic and functional dome head: the low, round pan head provides maximum bearing surface and a clean appearance, suitable for exposed connections in cladding and framing.
Direct threading technology for steel and aluminium: the screw drills and threads in a single action — no pre-punching, no accessories and no “dead time” on site.
Proven field durability: made of C1035 steel with a cold-galvanized coating — it doesn’t break, bend or disappoint (unlike cheap, undocumented alternatives).
An enormous range of options: 5 diameters (from ST3.5 to ST5.5), dozens of lengths from 9.5 up to 120 mm, PH2/PH3 bit — a complete solution for every specification.
Support and backing: designed for contractors and engineers who require engineering backing, load tables and compliance with stringent building codes.

Quick installation guide — self-drilling dome head screw (for steel)

Mark the drilling point: a light tap with a center punch for accurate centering will prevent the screw’s drilling tip from slipping at the start of rotation.
Prepare the right driver: use a driver with the speed and torque per the table. An impact driver may be used — but only if you stop immediately once the screw’s dome head seats against the profile, to prevent stripping the thread.
Drive perpendicular to the profile: hold the driver at 90 degrees to the material with steady, continuous pressure. Driving at an angle breaks the drilling tip and produces a weak, defective connection.
Stop when the dome head seats: when the screw’s dome head reaches the surface and the required tightening torque is achieved — stop. The dome head should sit flat and even against the fastened material.

All dome head and countersunk (flat) head screw models in the Adit catalog

ABR: classic self-drilling dome head screw (Pan Head / Dome Head), cold-galvanized, PH bit. The most common series for connecting steel and aluminium profiles when a low, aesthetic screw head is required.
ABR A2: identical to the ABR but made of 304SS stainless steel with a passivation coating. Suited to aggressive environments, outdoors, coastal areas and the chemical industry — when a stainless steel self-drilling dome head screw is required.
ABP: self-drilling countersunk (flat) head screw (Counter-Sink / Countersunk Head) — cold-galvanized, PH bit. Intended for locations where the screw must be flush with the surface. Provides direct self-drilling with no pre-drilling.
ABP-T: self-drilling countersunk (flat) head screw with a Torx (TX) bit. Offers superior bit anti-slip and higher tightening torque compared to PH, suited to industrial environments.
ABRC: self-drilling dome head with a Square bit. Serrations on the underside of the head prevent rotation — particularly suitable when maximum tightening stability is required.
ABRT: self-drilling dome head with a Torx (TX) bit. Combines the aesthetics of the dome head with superior bit anti-slip — for fast, precise work.
PS3 / PSL: extra-long screws for fastening insulated panels (sandwich panels). Always supplied with an EPDM sealing washer for perfect protection against rain.

Engineering consultation + a quality self-drilling dome head screw = a complete solution

The market is flooded with cheap self-drilling dome head screws from obscure sources that often break under load, drill slowly or rust quickly. What sets Adit Ltd. apart from other suppliers is knowledge and standards compliance. The company’s engineers are available to assist in calculating and selecting the screw diameter, screw length and the correct model (including corrosion-resistant self-drilling dome head screws), saving the costs of field failures and enabling standard, approved structural design.

Frequently asked questions

What is the difference between a self-drilling dome head screw and a regular self-tapping screw?

A self-drilling dome head screw includes a dedicated drilling tip at its point, which lets it drill its own pilot hole in steel independently — with no need for an external drill. By contrast, a self-tapping screw cuts and forms the nut thread but requires a pre-drilled pilot hole of the appropriate diameter before threading. Using a self-drilling dome head screw saves valuable time and tools on site.

What is the difference between a dome head and a countersunk (counter-sink) head on a self-drilling screw?

A self-drilling dome head screw (ABR) is suited to cases where the head will remain visible above the surface: the low, wide dome head provides a large bearing surface, high pull-out resistance and a clean, presentable appearance. A self-drilling countersunk head screw (ABP) is intended for locations where the screw must be fully recessed into the material and flush with the surface — common in cladding that should not be touched and in connections requiring a perfectly smooth surface. The countersunk head requires pre-forming the recess (counter-bore) in the top material.

How do I know which diameter of self-drilling dome head screw to choose?

Selecting the diameter of the self-drilling dome head screw depends on the thickness of the profile you plan to penetrate: an ST3.5 screw is intended for thin steel of 0.7-2.2 mm. An ST4.8 screw (a very common diameter) suits steel thicknesses up to 4.4 mm. An ST5.5 screw suits thicknesses up to 5.25 mm. It is also important to ensure that the screw length matches the sum of all material layers to be penetrated.

Does a self-drilling dome head screw made of regular steel rust outdoors? Is there a stainless steel version?

The standard ABR screws come with a cold-galvanized coating intended for protected indoor environments. When installing a self-drilling dome head screw for outdoor cladding (especially near the sea), you must use the stainless steel version — ABR A2 (304 stainless steel SS304/A2 with a passivation coating). This screw offers excellent corrosion resistance for years, even in aggressive environments.

Why does the PH bit of a self-drilling dome head screw slip? What can be done?

A PH (Phillips) bit tends to slip (“cam out”) when the tightening torque is high. For jobs requiring higher torque, it is better to choose the dome head with Torx bit — ABRT or dome head with Square bit — ABRC models. These bits provide much better torque transfer and virtually eliminate slipping. Also make sure to use the correct bit size (PH2 for ST3.5-ST4.8 screws, PH3 for ST5.5) and in good condition.

Can a steel self-drilling dome head screw be used to fasten aluminium?

Yes, but with a critical caveat: if you thread a regular steel screw (such as the standard ABR) into aluminium that will be exposed to moisture or water, galvanic corrosion will form that will destroy the connection and the aluminium. To prevent this, for outdoor or damp-environment aluminium connections, use only the stainless steel ABR A2 series. For aluminium connections in a protected environment, the standard ABR can also be used.

What is the difference between Nrd (design load) and the characteristic failure load (Nrk)?

The characteristic failure load (Nrk) is the value at which the screw or profile collapses in destructive laboratory testing — this is the figure shown in some of the tables. The design load (Nrd) is the value after dividing by a safety factor, and Nrec is the recommended service load (full, long-term service). You must not design a project based on the failure load! Adit provides engineers with all the data required to perform the correct calculation.

Can a self-drilling dome head screw be removed and re-threaded into the same hole?

It is entirely possible to remove the screw and release the connection, but it is strongly not recommended to reuse the same self-drilling dome head screw in the same hole again. Threading in thin steel slightly damages the screw thread and the hole itself, and re-threading may significantly impair the pull-out capacity. In such cases it is better to move up to a larger screw diameter or to place the new screw a short distance from the old hole.

What is the difference between an ABR self-drilling dome head screw and one from the ABE series?

Both series are self-drilling screws with a dome head, but they differ in key parameters: ABR is a screw with a low pan head and a PH bit, intended for connecting steel and aluminium profiles. ABE is a self-drilling screw with a hex washer head — the hexagonal head allows the use of a wrench and provides higher tightening torque. The choice between the models depends on the specification’s needs: when an aesthetic, flat head is required — ABR; when very strong tightening with a wrench is required — ABE.

ABR (dome head) vs ABP (countersunk head) — when do you choose each?

Self-drilling dome head screw (ABR) — the head protrudes slightly above the surface, provides a large bearing surface and high pull-out resistance, and suits most profile, cladding and framing connections. Self-drilling countersunk head screw (ABP) — the head fits fully into a cone in the material and leaves a completely smooth surface, suitable when full flushness is required (for example, in panels that are later machined, coated or subject to frequent physical contact). For the right choice, consult with Adit’s engineers.

Planning a steel or cladding connection? Tell us the profile thickness, material and load — our engineers will recommend the right ABR diameter, length and model and send you the load data.

Talk to our engineers