PSL Long Self-Drilling Steel Screw

A dedicated long self-drilling steel screw for fastening sandwich panels directly to steel or aluminium beams 6–12 mm thick — a 15 mm Long Point (No. 5), dual-diameter 6.3/5.5 mm geometry and approved pull-out and shear data.

Long Point No. 5 — 15 mmDrills steel up to 12 mmDual-diameter 6.3 / 5.5 mmSandwich panels to beamsEPDM hermetic sealLengths 75–285 mm

The Adit self-drilling screw family

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

PS3Self-drilling · sandwich panels on straps/purlins · up to 6 mm PSLLong point 15 mm · beams 6–12 mm · dual-diameter 6.3/5.5 ABEI304 stainless · aggressive, coastal & chemical environments BIE / BIE A4Bi-metal · drills hard & stainless steel (A4/316SS) AUTO / BAUTOExtra-long drill point · up to 12 mm steel · bi-metal option ABP / ABRAesthetic heads · countersunk conical & round flat RSZ / RSWafer head · fine seams & frames (A2 option)

Technical specification — geometry and dimensions

Uniform, precise dimensions across every length in the PSL series.

Parameter	Value / range	Unit
Screw diameter (P2 – body)	5.5	mm (ST5.5)
Outer diameter incl. thread (P1 – head)	6.3	mm (ST6.3)
Head diameter (dk)	10.5	mm
Washer diameter (C)	5.46	mm
Head thickness (K)	4.1–4.5	mm
Hex socket (e)	8	mm
Thread pitch P1 (6.3 mm)	1.8	mm
Thread pitch P2 (5.5 mm)	1.05	mm
Drill point length (Long Point)	15	mm
Maximum steel thickness for drilling	up to 12	mm
Available lengths	75–285	mm

Approved technical data

The following data forms the basis for safe structural design with the PSL long self-drilling steel screw. All values in the tables are in kN per single screw, ST5.5 diameter (P2 screw body). Please note: the values listed below are characteristic failure loads (Nrk/Vrk). For engineering design, an appropriate safety factor must be applied. The designer must also verify the tear-out capacity of the profile itself.

PSL ST5.5 – fastening to a steel profile

Load parameter (kN)	Steel thickness 2 mm	Steel thickness 3.5 mm	Steel thickness 5 mm
Characteristic failure load – pull-out (Nrk)	5.4	8.7	9.6
Characteristic 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

PSL ST5.5 – fastening to an aluminium profile

Load parameter (kN)	Aluminium thickness 2 mm	Aluminium thickness 4 mm	Aluminium thickness 5 mm
Characteristic failure load – pull-out (Nrk)	2.0	7.6	9.6
Characteristic failure load – shear (Vrk)	4.8	4.8	4.8
Design load – pull-out (Nrd)	0.9	3.5	4.8
Design load – shear (Vrd)	3.7	3.7	3.7
Recommended load – pull-out (Nrec)	0.7	2.5	3.4
Service load – shear (Vrec)	2.6	2.6	2.6

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

Part numbers and lengths

Part no.	Anchor type	Length (mm)	Small box (units)	Coating
PSL55075	PSL 5.5/6.3×75	75	500	Cold galvanised
PSL55085	PSL 5.5/6.3×85	85	500	Cold galvanised
PSL55105	PSL 5.5/6.3×105	105	500	Cold galvanised
PSL55130	PSL 5.5/6.3×130	130	250	Cold galvanised
PSL55150	PSL 5.5/6.3×150	150	250	Cold galvanised
PSL55175	PSL 5.5/6.3×175	175	200	Cold galvanised
PSL55200	PSL 5.5/6.3×200	200	200	Cold galvanised
PSL55230	PSL 5.5/6.3×230	230	200	Cold galvanised
PSL1955255	PSL 5.5/6.3×255	255	200	Atlantis C4
PSL1955285	PSL 5.5/6.3×285	285	200	Atlantis C4

Any screw can be supplied with an EPDM washer on request. The 255 mm and 285 mm lengths come with an EPDM washer as standard.

What is the PSL long self-drilling steel screw?

The PSL long self-drilling steel screw (Long Self-Drilling Screw for Sandwich Panels) is a dedicated self-drilling steel screw for fastening insulated panels (sandwich panels) directly to metal beams on roofs and facades. Unlike shorter screws intended for thin straps, the PSL features a long drill point (Long Point – No. 5) capable of drilling and penetrating steel or aluminium profiles up to 12 mm thick – with no pre-drilling required.

What sets the PSL apart is its unique two-stage geometry: the screw is built from two threaded zones of different diameters. At the leading part of the shank (P1, the drill-point side) the diameter is 6.3 mm (ST6.3), and along the rest of the shank (P2, the head side) the diameter reduces to 5.5 mm (ST5.5). This distinctive design – combined with the long drill point – makes the PSL the ultimate long self-drilling steel screw for fast, safe and code-compliant work on thick beams.

The screw is intended for fastening sandwich panels to beams (such as IPE/HEA beams) and to thick structural profiles 6–12 mm thick. It comes with an EPDM washer for full sealing, and enables fast, code-compliant work even on large and complex projects.

The dual-diameter geometry — what makes this long self-drilling screw special

Unlike a regular self-drilling steel screw with a single diameter and a short drill point, the PSL is built with three separate, complementary functional zones:

Long drill point – 15 mm (Long Point No. 5): this is the fundamental difference between the PSL and the standard PS3. The long drill point makes it possible to penetrate steel and aluminium beams up to 12 mm thick – twice the capacity of a standard self-drilling steel screw. No pre-drilling, no delays.
P1 – 6.3 mm diameter, 1.8 mm pitch (drill-point side – in the beam profile): the first, larger thread enters the beam and creates a strong grip in the load-bearing material. The coarse pitch enables fast progress through the thick steel.
P2 – 5.5 mm diameter, 1.05 mm pitch (head side – in the panel): the finer pitch connects the panel and creates a “clamping” effect that draws the panel toward the beam. The difference between the two diameters and the two different pitches ensures a tight, durable connection for years.

Why do the different pitches matter? On the PSL the pitches are not identical (1.8 mm versus 1.05 mm) – unlike the PS3, where both are 1.8 mm. The difference creates an active “pull” that draws the panel toward the beam during driving, ensuring a hermetic, uniform connection even with very thick panels.

The advantages of the PSL — not every long self-drilling screw is the same

Long drill point (Long Point No. 5): a 15 mm drill point – double that of standard competitors – enables direct penetration of steel and aluminium beams 6–12 mm thick with no pre-drilling.
Unique dual-diameter geometry: 6.3 mm diameter at the start (P1, 1.8 mm pitch) and 5.5 mm along the rest (P2, 1.05 mm pitch) – a structure that increases pull-out load and prevents self-loosening even under heavy wind loads.
Approved technical data: precise pull-out and shear values for every steel and aluminium profile thickness, enabling safe, code-compliant engineering design.
Proven field durability: made of C1035 steel with a cold-galvanised coating (Atlantis C4 for the long lengths) – a long self-drilling steel screw that does not break, bend or disappoint under thick-beam conditions.
Dedicated EPDM washer: all screw lengths are available with an EPDM washer for a hermetic seal; the 255 mm and 285 mm lengths come with the washer as standard.
Wide range of lengths: 75–285 mm in 10 different lengths – a long self-drilling steel screw for every panel thickness and every type of beam.
Engineering support and backing: ADIT engineers are available to help select the model, calculate loads and ensure compliance with stringent building codes. Tel: 054-7976110.

Quick installation guide — PSL on beams

Mark the entry point: a light tap with a centre punch for accurate centring will prevent the long drill point from slipping at the start of rotation. This is especially important when drilling smooth beams.
Prepare the right driver: drilling speed in steel: 1,000–1,800 rpm. Drilling speed in stainless steel: 600–1,000 rpm. Maximum drilling time: 11 seconds. Maximum installation torque: 10.4 Nm. An impact driver is recommended – but stop immediately once the screw head seats against the panel.
Drive perpendicular to the profile: hold the driver at 90 degrees to the material with steady, continuous pressure. Driving at an angle causes the drill point to break, resulting in a weak connection and poor sealing.
Stop when the screw seats and the washer is compressed: once the screw seats – stop. You must make sure the EPDM washer is evenly compressed but not completely crushed – this is the key to a hermetic seal against rain and water penetration into the panel.

Engineering consulting + a quality long self-drilling steel screw = a complete solution

The market is flooded with long self-drilling screws from unknown sources that break under load, drill slowly through thick beams, or corrode quickly under roof conditions. What sets ADIT Ltd. apart from other suppliers is its engineering knowledge and technical documentation: approved data for every profile thickness, support in choosing the right length according to panel and beam thickness, calculation of screw spacing according to wind and snow loads, and full compliance with building codes. This saves the cost of field failures and enables code-compliant, approved structural design.

Frequently asked questions

What is the PSL long self-drilling steel screw, and what makes it different from a regular self-drilling screw?

The PSL long self-drilling steel screw is equipped with a long drill point (Long Point, 15 mm) that enables direct penetration of steel and aluminium beams up to 12 mm thick – with no pre-drilling. A regular self-drilling steel screw (such as the PS3) has a shorter drill point (7.5–9 mm) and is intended only for thin straps up to 6 mm. In addition, the PSL has different pitches in its two threaded zones (1.8 mm and 1.05 mm) that create an active pull of the panel toward the beam.

What is the difference between the PSL and the PS3, and when do you use each?

PS3 is intended for fastening sandwich panels to straps/purlins – thin profiles up to 6 mm thick, with a No. 3 drill point (7.5–9 mm) and identical 1.8/1.8 mm pitches. PSL (the long self-drilling steel screw) is intended for fastening panels to beams – thick profiles 6–12 mm, with a No. 5 long drill point (15 mm) and different 1.8/1.05 mm pitches. The choice is simple: straps → PS3, beams → PSL.

How do you choose the correct PSL length according to panel thickness?

The formula: sandwich-panel thickness + beam thickness + a minimum 10 mm thread engagement in the beam = the required length. For example, a 120 mm panel on a 10 mm beam requires a screw of at least 140 mm, i.e. PSL55150 (150 mm). The table on the product page details the range of panel thicknesses suitable for each part number.

Why does the PSL long self-drilling steel screw have two different pitches?

Unlike the PS3, where the two pitches are identical (1.8 mm), the PSL is designed with P1 at a coarse pitch (1.8 mm) for fast penetration through the thick beam, and P2 at a fine pitch (1.05 mm) for a gentle, retained grip in the panel layer. The difference in pitches creates an active “pull”: P1 advances faster than P2 and draws the panel firmly toward the beam with every turn, ensuring tight contact and a sealed connection.

What is the PSL’s galvanic coating, and which environments is it suitable for?

Lengths up to 230 mm come with a cold galvanised coating (suitable for indoor environments and protected enclosures), and the 255 mm and 285 mm lengths come with an Atlantis C4 coating – an advanced coating that withstands harsh outdoor conditions and provides corrosion uniformity. For the most aggressive environments (coastal, industrial areas), consider a stainless-steel long self-drilling steel screw from the ABEI series.

What is the EPDM washer, and why is it critical on the PSL?

When fastening a sandwich panel to a beam, the PSL long self-drilling steel screw passes through the entire panel thickness and creates a hole on both of its faces – a point sensitive to rain penetration. The EPDM washer (a rubber disc resistant to UV rays and extreme temperatures) is compressed as the screw tightens and creates a hermetic seal around the hole. The 255 mm and 285 mm lengths come with an EPDM washer as standard; for the other lengths it can be requested with the order.

Can the PSL be used to fasten a panel to an aluminium profile?

Yes, the PSL is approved for fastening to aluminium, but two things are important: first, pull-out loads in aluminium are lower than in steel – you must follow the aluminium load table. Second, a steel self-drilling screw fastened into aluminium in an exposed outdoor environment can cause galvanic corrosion. In humid environments, it is recommended to switch to stainless-steel screws (ABEI).

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

The characteristic failure load (Nrk) is the value determined in destructive laboratory tests. You must not design a project according to the failure load! Engineers divide Nrk by an appropriate safety factor (per international standards) to arrive at Nrd (the safe design load). For conservative design, the recommended load (Nrec) can also be used. ADIT provides all three values in the technical tables of the PSL long self-drilling steel screw.

Why does the drill point of my long self-drilling steel screw break?

The common causes: driving at an angle (not 90 degrees), using a speed higher than 1,800 rpm, attempting to drill a profile thicker than 12 mm (beyond the PSL’s capacity), uneven pressure at the start of drilling, or using a long self-drilling steel screw from cheap, unapproved sources with soft steel. For profiles thicker than 12 mm, consider using the AUTO series with an extra-long drill point.

Can the PSL be removed and re-driven into the same hole?

The long self-drilling steel screw can be removed, but it is strongly not recommended to re-use the same screw in the same hole. The double thread (6.3 + 5.5 mm) damages both the screw thread and the hole. Re-driving will significantly reduce pull-out capacity. In cases of disassembly, replace it with a new screw and position it at a new point, or move up to a larger diameter.

What is the recommended screw spacing for PSL screws in a roof panel?

Screw spacing depends on the wind and snow loads in the area, the panel type, the roof geometry and the beam spacing. There is no single “standard spacing” – the designer must calculate the spacing according to the relevant service loads and the loads of the PSL long self-drilling steel screw from the tables. ADIT engineers are available to help with this calculation. Contact us at Tel: 054-7976110.

Fastening sandwich panels to thick beams? Tell us the panel thickness, beam thickness and material — our engineers will select the right PSL length and run the pull-out and shear calculation.

Talk to our engineers