Self tapping metal to wood screws and roofing screws
Basically, all self-drilling and self-tapping screws are able to tap threads, where the main difference is that self-tapping screws normally come with either a blunt head, sharp point, or a reduced drill point.
Blunt headed screws such as the TRUSS-Tite™ is designed for truss components assembly, fixing into steel. These types of steel normally come with pre-punched or pre-drilled holes, and the blunt, slightly tapered leading threads makes it easier to fix the sheets down.
Our sharp pointed TIMBER-Tite™ are designed for fixing roof sheeting to timber. The longer versions such as the T17CG1265C3N or T17CG1250C3N are designed for crest fixing and shorter versions such as the T17H1020C3N are designed for valley fixing. People ask why screws should be fixed down on the crest but not the valley. The main reason being water runs by gravity and flows to the lowest point, and if fixed on the valleys on rooftops, might increase the risk of water pooling around the screws and with time, cause rust.
Shorter self-tapping screws which come with what we call a “reduced” drilling point, provides the same function as a sharp drilling point, but drills faster through thin metal sheeting, and is much more effective at clearing off excess swarf, as it is difficult if impossible to add flutes on smaller sharp pointed screws to due manufacturing limitations.
For roofing sheet fixing screws, always check if they come with a knurled, fluted, or slotted shank, and if the upper threads are larger in diameter compared to the lower threads. You might notice that the majority of BDN self-drilling and self-tapping roofing screws are equipped with both. The larger diameter upper threads provide good pullout strength for the whole setup under high winds and the slotted Scratshank design clears out excess swarf which might damage EPDM washers if leftover, which could result in leaks.
Self-tapping screw head types
A self-tapping screw has the ability to tap threads as it is driven into the material. It is often used only to describe a specific type of thread-cutting screw intended to produce threads in various types of materials, with sheet metal and wood being the most common.
BDN Fasteners offers a range of self-tapping screws. The screws come with either a self-drilling tip for metal or pointed tip for timber. After the tip creates a pilot hole, the thread then taps the metal or wood the screw is affixed to.
On head types. Screws are available in many different head types. Some head types are very application specific, and others for more varied and general applications. Head types are usually manufactured according to set standards according to the region used, though some might tweak or even tailer the design here and there in order to meet special requirements.
BDN Fasteners are manufactured according to the tried-and-true Australian AS standards, offering a good balance between cost and performance, and backed with an industry leading warranty.
BDN Fasteners (Broaden Worldwide Co., Ltd) is an ISO-9001 Certified Quality Supplier-Manufacturer of Australian Standard AS3566 self-drilling and self-tapping screws in various coatings for steel to steel to steel to timber applications. Our headquarters are in Taiwan and we operate sales and marketing offices in India and Thailand.
Founded in 2009.