Wood Screws FAQs
What are wood screws?
Wood Screws are metal threaded fasteners designed for use in timber - hard wood and soft wood, chipboard and MDF.
Wood Screws are available in a number of different materials including Hardened Steel and Stainless Steel. They are also available in Brass and Unhardened Steel.
Hardened Steel Wood Screws can be plated with different coatings to give various levels of corrosion protection.
The most common coating is Zinc Plating with either a clear passivation – Silver in colour or yellow passivation – Golden in colour, and less commonly black passivation.
In addition, there are Organic coatings available which give higher levels of corrosion protection, most common is the Green coating applied to decking screws.
Wood Screws can also be powder coated with polyester paints to specific RAL Numbers for an exact colour match.
Stainless Steel Wood Screws are available for exterior or wet environments.
Two Grades are available A2 (302,304) which gives good levels of corrosion resistance in non-acidic and non-marine environments.
A4 Marine Grade (316) Stainless Steel Wood Screws are available for harsher environments and give good levels of corrosion resistance in Marine environments.
Under certain conditions both A2 and A4 grade stainless steel will corrode but both will give better corrosion protection than most plated screws.
The most common drive for Wood Screws is Pozi but Wood Screws are also available with TX drive and less commonly these days Slotted.
TX drive is cog shaped and less likely to be damaged when screws are used into harder material, when very long Wood Screws are used or with Stainless Steel Wood Screws which
are softer than Hardened Steel Wood Screws.
Wood Screws are available with 5 main head styles:
- Flat Countersunk which sits flush to the work piece surface and is the most common head style and is used for wood to wood joints, hinges and countersunk brackets.
- Pan Head which is domed and sits on top of the work piece and used to attach flat plates and brackets to timber materials.
- Flange Head or Wafer Head which again sits on top of the work piece, is wider and more shallow than Pan Head and has greater resistance to pull through allowing higher clamp loads to be applied.
- Hex Head and Hex Washer Head Wood Screws are also available which again allow higher torque values to be applied.
- Wood Screws are available in a number of thread diameters from 2.5mm to 12.00mm and lengths from 10mm up to 600mm and beyond.
What types of wood screws are available?
There are many different types of Wood Screws available for different applications.
Single Thread Wood Screws for general use in Timber Chipboard and MDF.
High Performance Wood Screws for use in harder materials. These typically have Self- Countersinking Ribs on the head and Cut Point for easy driving.
They can also have a Spiral Reamer above the threads to help prevent jacking.
Structural Wood Screws for use in Timber Framed Buildings, Glulam Cross Laminated Timbers, Offsite Construction and SIP Panels, Roof Decks and Floor Cassettes.
These have a TX Drive and usually a cut point and are available with Countersunk or Flange heads. Cap or Cylinder Heads are also available.
Popular Thread Diameters are 6.0mm and 8.0mm and they are available up to 300mm long for 6.0mm and 500mm long for 8.0mm diameters.
Specialist Wood Screws are available for Decking and Cladding applications. These are generally used in exterior applications and so are either Stainless Steel or have a special Green coating for enhanced corrosion protection. These can have Small Heads to avoid splitting, Cut Points or Drill Points for easy driving and Self Countersinking Ribs on the head for flush fitting.
They are also available with painted coloured heads to match different coloured materials.
Can I use wood screws in other materials?
Wood Screws can be used in Soft Woods, Hard Woods, Chipboard, MDF and some Plastics
What is the difference between wood screws and drywall screws?
Wood Screws are very different to Drywall Screws.
They are available in many more different sizes and coatings and are generally Pozi Flat Countersunk whereas
Drywall Screws are Phillips Bugle Head which causes less damage to the plasterboard.
Drywall Screws can self-drill into steel studding up to 2mm thick whereas Wood Screws are not suitable for use in steel.
Can wood screws be used in outdoor projects?
Wood Screws can be used on outdoor projects but must have a high corrosion resistant coating or even better be made of Stainless Steel.
Coated screws will corrode eventually and quite quickly if they are exposed to salt water or acid within timber.
The best material for external applications is A4 Marine Grade (316) Stainless Steel this gives very good corrosion resistance, is better than A2 (302 304) Stainless Steel and is often used in marine environments.
How to remove a screw with no head from the wood?
There are a number of ways to remove broken screws from timber. If enough of the screw is exposed it can be manually removed by unscrewing using locking pliers or more quickly by
clamping the exposed shank in the chuck of a cordless electric screw driver and reversing the screw out of the timber.
If not much of the screw is exposed it is a little more difficult. You could try using a chisel to remove some timber from around the broken screw exposing more of the screw to grip with pliers or electric screw driver.
Alternatively you could remove the screw using a plug cutter then make a new bigger plug from scrap material using the next size up plug cutter.
The new plug should be glued into the hole where the screw was removed then cut flush using a flush saw.