DIN 7504 P · HVAC Ductwork · Light Gauge Framing · ISO 15482
The DIN 7504 P pan head self drilling screw is the workhorse fastener for HVAC ductwork, skin sheet to steel connections and light gauge steel fabrication across India. Its rounded dome head provides a clean, neat finish above the surface with a good bearing area — sitting between the flush CSK head and the bulkier hex head in the DIN 7504 range. It drills, taps and fastens in a single operation with no pilot hole. Available in M3.5, M4.2 and M4.8 in zinc plated and stainless steel. The international equivalent standard is ISO 15482.
HVAC ductwork — galvanised sheet to duct frame assembly
Skin sheet to steel — thin cladding sheet to light steel secondary frame
Stitching — joining one thick and one thin steel plate together
Residential and commercial light gauge steel frame construction
Electrical enclosures, switchboards and panel fabrication
General sheet metal fabrication — thin gauge metal-to-metal connections
Rounded dome pan head — neat finish above surface with good bearing area
Phillips drive — self-centering, fast installation with standard screwdriver bit
Non-walking drill point — fast material engagement, no pilot hole needed
Drills, taps and fastens in one single operation
Zinc plated for indoor use — stainless steel for outdoor and humid environments
Heat treated carbon steel — consistent hardness and drill point performance
White Zinc
Stainless Steel
Drill Point #2 penetrates up to 2.0mm steel. Drill Point #3 penetrates up to 4.0mm steel.
The pan head self drilling screw sits in the middle of the DIN 7504 head type range. It has a rounded dome profile that provides a neat, clean finish above the surface — unlike the flush CSK head which disappears into the material, and unlike the bulky hex head which requires a socket driver. The pan head is driven with a standard Phillips screwdriver bit, making it the fastest and most versatile option for general sheet metal assembly, HVAC ductwork and light fabrication work where appearance and access matter.
The rounded head also provides a moderate bearing surface — larger than a CSK head but smaller than a hex washer head. This makes it suitable for thin gauge steel connections where some surface contact is needed to distribute the clamping load, without the need for an additional washer.
Rounded dome — sits above surface. Phillips drive. Moderate bearing area. Best for HVAC ductwork, skin sheet, light fabrication and general sheet metal. Fast installation, easy removal.
Hexagonal head — sits above surface. Socket drive, higher torque. Large bearing area with integrated washer flange. Best for structural roofing, purlin connections and weather-sealed applications.
90° countersunk — sits flush with surface. Phillips drive. No bearing area above material. Best for window frames, door frames and applications requiring a completely flush finish.
HVAC duct assembly is one of the highest-volume applications for pan head self drilling screws in India. Rectangular and round duct sections in galvanised steel are joined using M3.5 and M4.2 pan head self drilling screws with Drill Point #2, which penetrate the thin gauge galvanised steel cleanly at high speed without a pilot hole. The pan head sits neatly above the duct surface where it is clearly visible for inspection, and can be removed easily for maintenance if the duct needs to be opened.
For HVAC duct-to-frame connections — where a thicker steel bracket or frame section is involved — the M4.2 or M4.8 with Drill Point #3 provides the penetration needed for steel up to 4.0mm without snapping the drill point.
Installation note
For HVAC ductwork, space pan head screws at 150mm to 200mm centres along duct joints. Use a torque-limiting driver to prevent over-driving into thin gauge galvanised steel — over-driving strips the thread and weakens the duct joint.
A key application of the pan head self drilling screw is stitching — the process of joining one thicker steel section to one thinner steel section, or joining two overlapping thin steel sheets together at the lap joint. In pre-engineered buildings, wall panel stitching, roof panel side laps and partition wall construction, this operation is performed with M4.2 pan head self drilling screws at regular centres along the joint.
The pan head provides the right combination of bearing area and head height — enough to clamp the sheets together firmly without the bulk of a hex head that would protrude visibly along the panel lap line.
DIN 7504 P specifies a pan head self drilling screw with a rounded dome head and Phillips drive. It drills, taps and fastens in one operation with no pilot hole. The ISO equivalent is ISO 15482. Used for HVAC ductwork, skin sheet to steel, stitching and general sheet metal fabrication across India.
A pan head is driven by a Phillips screwdriver bit and sits with a rounded dome above the surface — suited for HVAC, sheet metal and light fabrication. A hex head requires a socket driver, delivers higher torque and is used for structural roofing and purlin connections with EPDM sealing washers. Pan heads are faster to install; hex heads provide greater clamping force and weather sealing.
Yes — pan head self drilling screws in M3.5 and M4.2 with Drill Point #2 are the standard fastener for HVAC duct assembly in India. They penetrate thin gauge galvanised steel cleanly without a pilot hole, leaving a neat head that is easy to inspect and remove for maintenance.
We stock DIN 7504 P pan head self drilling screws in M3.5 (#6-20), M4.2 (#8-18) and M4.8 (#10-16). Lengths from 10mm to 50mm. Zinc plated and stainless steel. Call +91-9448239476 for bulk pricing and availability across India.
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