Types of screws for metal installation, BDN Fasteners has developed 9 types of screws for metal which are split into 5 categories for you to choose from.

The Origin of Screws

BDN Fasteners specializes in manufacturing self-drilling and self-tapping screws, and a wide selection of types of screws for metal fixing.

 

Although the origin of screws is up for debate and was known to be used as early as the first century B.C., and has evolved to a plethora of length, sizes, and specific usage, the basic function has remained to be affixing two objects together, securely.

 

BDN Fasteners

Due to the ever-changing building regulations and codes which also differs from country to country, BDN Fasteners have developed 9 types of screws for metal which are split into 5 categories.

 

Regardless of the design and purpose these screws are aimed for, BDN Fasteners for metal include basic and proprietary designs which are manufactured to the highest standards, no corners cut.

• Basic Designs –
  1. Mechanical Properties – Follow AS3566 standards for Self-drilling screws for the building and construction industries.
  2. Corrosion Resistant Properties – Surface coating designed to withstand the elements and can be adjusted to cope with specific weathering conditions.

• Proprietary Designs – Specific designs offer unique properties that provide superior performance for all BDN types of screws for metal.
  1. Trident Drill Point (Pat.) – Provides fast, steady and pinpoint precision drilling performance, effectively clears swarf and drills through 6mm thick steel.
  2. “S” Swirl Drilling Tip – Creates a larger area of engagement from the initial drill drive.
  3. Improved “Cutting Edge” Design – Larger, curved cutting blade edge lower manual load required.
  4. Scratshank / Double Scratshank – Effectively cuts and break out metal filings around the drill hole, keeping it free of damage to sealing washers during installation.

 

Types of Screws for metal

The types of screws for metal include but are not limited to the following series:
	METAL-Tite™ Fixing Cladding to Metal Fixing to Thick Steel Insulated Sandwich Panel Screws for fixing to metal Crest Fixing Fasteners for Fixing Roof Sheeting to Metal Concealed fixing for brackets or fixing clips for wall cladding.
	DUAL-Tite™ Duofix 2 IN 1 Roofing Screw for Fixing Roof Sheeting to Light Metal and Timber.
	TRUSS-Tite™ For the assembly of metal truss components through pre-punched holes.
	FRAME-Tite™ Flat topped frame screw designed for stud to plate connections and connection lintels to plate without pre-punched holes.
	POLYXPAND™ Fixing Polycarbonate Sheeting to Metal.  Offered in Crest Fixing and Valley Fixing screws for metal versions.
	POLY-FAST™ Features a fail-safe thermal expansion hole cutting washer design for fixing Polycarbonate Sheeting to Metal.

 

For more information on BDN types of screws for metal, please contact the dealer near you, or send us an email at info@broadenal.com.tw.

 

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There will come a time when you will encounter a seemingly impossible task, a piece of steel so thick and heavy duty that even your already awesome BDN No.3 point TEK screws in the toolkit cannot handle.  There will come a time when you the piece of steel in front of you may be tagged as “mild steel”, but in fact is composed of complex, unevenly distributed alloys, which creates a big challenge for regular self-drilling tips, and almost impenetrable.

 

One of the most important job a self-drilling screw has to muster, is clearing out excess material, or swarf, while drilling.  Having a hardened drilling point and sharp cutting blades only helps with the initial drill and drive, but without a flute long enough and designed correctly to bring out the excess during the spiraling action, iron shavings left in the hole are heated easily from all the spinning, causing the drill to burn out.  Once this happens, there is little to no chance of penetration with the screw, and you’ll have to start all over again.

 

A lot of big brand names are marketing their screws as either self- as TEK screws for thick steel, heavy duty self-drilling metal screws, or self-drilling screws for thick steel, capable of drilling through 12.5mm steel and above, though not many can perform as advertised.

 

Not for BDN METAL-Tite™ Heavy Section Fasteners.  Ours perform flawlessly, without fail.

 

 

BDN METAL-Tite™ heavy section, penetrates 12.5mm thick steel with ease.  The patented Thunder-Shot drill point prevents wandering during the initial drill drive, clears out swarf swiftly and efficiently.  The whole screw is coated with BN3 silver coating, which consists of multiple layers of specially formulated, corrosion resistant chemicals, and can easily withstand 1000hrs of salt spray test (ASTM B117), and 7 Kesternich cycles (DIN50018 2.0 SFW).

 

BDN METAL-Tite™ heavy section screws are also offered in a special 16mm thick steel penetration version.  Designed to not only drill through thick, hardened, or complex alloy steel, but can also pass stringent 1mm + 2mm + 9mm, and 2mm + 12mm penetration tests.  The most demanding part of these two tests is to withstand the impact force on the drilling tip when it passes through the first and/or second sheet, and hits the final thick hardened layer of steel.  Imagine the wear and tear, plus heat buildup of the drilling tip during the first and/or second process.  Nevertheless, BDN Heavy duty self-drilling metal screws pass these two stringent tests with flying colors.

 

 

Please contact your nearest BDN Fasteners dealer for further information.

Internal roof insulation

Thermal insulation, which is required mainly for homes in order to slow down the flowing in or out of heat, is often added to walls, roof, ceilings, or floors.  As heat primarily escapes through conduction or physical contact with the colder temperature outside, construction and insulation of walls and roofs are crucial to keeping heat inside.

 

For buildings that were built with poor roof or wall insulation, remodeling could become a big burden, which usually involves taking off of the original roofing panels, and purchasing new insulation panels.

 

Steel sandwich panels are among the most commonly used material for building either industrial, commercial, agricultural, or public domains.  Sandwich panels can often be tailored to suit various thermal, acoustic or strength requirements by combing layers of different materials in different thicknesses to achieve the desired effect.

 

As mentioned in our other article: Step by step tutorial on choosing the correct screw type for roofing applications, it is important to understand and choose the correct screw type of the job.  BDN Fasteners offer a complete fastening solution which consists of various screw types for your insulated roofs or walls.

 

METAL-Tite™ Self-Drilling Screws

BDN Metal-Tite Series sandwich panel screws are made to match various sandwich panel thicknesses; with additional features such as an enlarged hex washer flange to fully cover fully compressed EPDM washers and holes, anti-static EPDM washer to prevent galvanic corrosion, double thread design to increase pullout values, Scratshank to clear excess swarf, and Ruspert anti-corrosive coating for extended lifespan.

 

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BDN Metal-Tite Stitching Fasteners can be used to fix panel to panel side lap, or panel to end lap of light gauge, lightweight steel.

 

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BDN Metal-Tite Wafer Head or Flat Top Concealed Frame Fixing Fasteners for low profile fixing with no visible protrusions which might create interference, creating an aesthetically pleasing flat surface upon installation.

 

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BDN Metal-Tite Truss to Plate connecting fasteners for fixing steel trusses to steel plates or beams which is pretty common on frame and structures for internal roof insulation or wall panels.

 

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Metal roof leaks around screws:

There are lots of contributing factors when it comes to roofing leaks.  A properly driven screw will have achieved the following steps and as a result, provide the perfect weather seal.

Driven straight, perpendicular to the material it is fastened on to.

Adequate, clean penetration with no excess swarf protruding or overhanging from the drilled hole.

Driven until the gasket is compressed firmly against the surface.

 

Below is a list of common causes of metal roof leaks.

 

1. Choosing an incorrect screw:

Metal roofing screws are usually designed for fixing thin roofing sheets onto steel purlins, trusses or timber underneath.  Depending on the thickness of steel underneath, correct drilling point sizes must be chosen in order to penetrate.  Most suppliers will provide a list with corresponding drilling capacities to their screws.  Read through the list carefully and don’t hesitate to ask questions.

The length of the screw is also important. The length of screw required can be calculated by adding the depth of the roofing sheet corrugation, plus the thickness of the purlin/truss underneath plus at least 2 to 3 full thread lengths to ensure proper fastening.  Don’t forget that the thickness of the bonded EPDM washer or Domed BAZ washer should also be taken into consideration.

Thread type should be considered.  A rule of thumb is, coarse threads for thinner sheets (<4.5mm), and fine threads for thicker sheets (>4.5mm).  This will ensure the fixing to have adequate pullout values against pressure from high winds or snow.

 

2. Over–driven screws:

The rubber gasket should seat firmly but not over compressed against the surface.  The rule of thumb is, the gasket should not be bulging at the sides of the washer flange, or even to the point of being squished.  Workers should take extra care while making an attempt to ensure a tight seal between the metal roofing and the screw head because an over-torqued washer loses its elasticity, breaks down prematurely, and oftentimes disintegrate due to over-exposure to the elements.

 

3. Under-driven screws:

This is an easy one.  An under-driven screw does not provide sufficient pressure to the washer to create a firm seal against the surface.  This may happen due to incorrect drilling tip capacity selection and therefore could not adequately penetrate the metal substrate underneath to reach the desired depth.

 

4. Misaligned or skewed drilling:

A misaligned or crooked driven screw will result in the rubber washers not seating properly against the surface, which means insufficient seal of the hole, or one side over compressed, resulting in premature damage to the gasket.  Another sometimes overlooked risk is the skewed side of the steel washer or hex washer flange digging in, deforming or sometimes even cracking the surface, which also contributes to leakage.

 

 

Some screws have extra features built in to enhance performance; oftentimes poor choice of fixings become the weakest link in a seemingly strong building structure.  BDN Metal-Tite® series roofing screws come with an enlarged hex washer flange, anti-static EPDM washer, double thread, Scratshank, and Ruspert anti-corrosive coating.

• The large washer flange is designed so that the EPDM washer will remain fully covered after compressed.
• Anti-static EPDM washers prevent galvanic corrosion.
• The larger diameter upper thread close to the hex washer flange increases pullout values on thin metal sheets.
• Scratshank clears out excess swarf, smooths out the drilled hole, and prevents damages to the EPDM.
• Ruspert anti-corrosive coating fully protects the screw from weathering and extends the lifespan of the screw and the sheets it is affixed to.

 

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