Self Drilling Screws Details

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Self Drilling Screws

Self Drilling Screws

Bhagawati Royal Roof DX Selfdrillers are high strength carbon steel self-drilling screws. They combine drilling, tapping and fastening in a single operation. Bhagawati Royal Roof DX Selidrillers are designed for use under the extreme conditions of construction site environments.


The high performance of Bhagawati Royal Roof DX Selfdrillers in terms of drilling speeds, fastening quality and durability reflect our twenty years of technology leadership, engineering and manufacturing expertise, In-depth knowledge of the practical requirements of end users within the construction industry enables serving specific trades and customers’ needs with full product performance confidence.

DX Drillpoint

The drillpoint is the key factor in self-driling screw performance. DX self-drilling screws are characterized Vy aggressive drillpoints that are made possible by state-of-the-art cold forging technology and tooling. Produced to Bhagawati Royal Roof’s exacting specifications, sharp and consistent points are found on all DX Selfdrillers.

The DX drillpoint closely resembles the drillpoint of a split-point twist drill bit. In the Bhagawati Royal Roof DX sell all the performance elements – point diameter, point angle, web thickness and flute length – have been carefully calibrated and combined for rapid penetration, The thin chisel edges assure immediate non-walking starts while raked cutting lips, wide spacious flutes and a tapered entry thread provide aggressive penetration with low manual pressure.

Drill Flute

The length of the drill flute I, controls the metal thickness drillable. The chips generated during the drilling process are evacuated through the drill flute. If the flute becomes completely embedded in material, drill chips will clog up in it and the cutting action will cease. This will cause the drill tip to anneal i.e. burn up, or break.

Point Length

Screw threads advance seven to ten times faster than the drill flute can remove metal. The point length PL (the unthreaded portion from the tip to the first thread) should be long enough to allow the drilling of all materials to complete before the first thread engages material. The point length therefore must be equal to, or greater than, the total thickness of material to be drilled, Where more than one sheet of material is involved the calculation of the total thickness to be drilled must include any insulation or voids between the top and bottom materials.


Bimatapps– Bimatapps are Bis– Metallic fasteners which are used for Aluminum roofing and cladding. Areas where there is high emission of gasses and other chemicals, aluminum sheets for roofing and cladding are a MUST, therefore using ordinary or even Class 3 fasteners doesn't really serve the purpose. Bimatapps are specially designed for such application. Having the entire body and the head made of SS 304 grade steel and the drill point alone made of carbon steel, it eliminates the chance of corrosion on the fasteners as well as the sheets.


Polytapps– Polytapps are fasteners specially designed for polycarbonate roofing and cladding. It is known that polycarbonate sheets have a high thermal expansion and contraction ratio, therefore in summers when the sheets expand, the hole created while drilling also expands allowing water to seep through and when in winter it contracts back, it tends to have an extremely tight grip on the fastener, resulting in cracking of the sheets. The flanged wings on the fasteners creates a slightly bigger hole on the sheet, which does not affect the fastener during the expansion and contraction of the sheets and to cover it, specially designed EPDM Dome washers are supplied along with the fasteners. This in turn eases the job and provides better results in future.


  • Steel to timber self-drilling screw with bonded washer
  • For fixing metal sheets to timber frames
  • Gash point gives easy initial penetration of metal up to 1.5mm thickness
  • Sharp threads ensure a low torque and strong fixing
  • Fully threaded for maximum versitility
  • Fitted with 16mm EPDM bonder washer (19mm available at the bottom of the table)
  • Standard 8mm (5/16") AF hexagon head drive
  • Sizes are thread diameter x screw length under head
d Diameter Hex Size s dc Flange Dismeter - max k - max Across Point e
6.3mm 8mm 5/16" 11 mm 5.45mm 8.71mm


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