A screw is a screw, right? Wrong.
Not alone should you know whether you want a woodscrew, a machine screw, a self-drilling or a carriage bolt, to name but a few.
You also might want to decide which, out of the ten or so different screw heads you want the screw to have.
A countersunk screw head, also known as a flat head, has a flat and level head. The aim of the countersunk screw head is to allow the screw to be level, or beneath, the surface it is being screwed into.
[caption id="attachment_2332" align="aligncenter" width="1200"] Countersunk Screw Head / Flat Head[/caption]
- Bugle Head
A bugle screw head is very closely similar to the countersunk screw. It also has a flat head. The side profile of the bugle screw head looks closely similar to that of a bugle instrument head. The difference between a standard countersunk and a bugle head is that the bugle head has a sort of rimmed conclave on the underside of the flat head. This curved inwardly edge makes Bugle Heads more suitable for soft material, like wood and dry wall.
[caption id="attachment_2338" align="aligncenter" width="1200"] Bugle Head Screw (Suitable for soft wood & drywall)[/caption]
A Round Screw Head has a rounded or domed head. The half of the screw that remains visible when screwed into the surface is rounded and domed. Roundhead screws tend to be used less frequently that Flathead screws. Where Flathead screws will be used to fix bookcases and cabinets etc, Roundheads may be used on machinery and with sheet material in which it would be too thin to use with countersunk screw heads.
[caption id="attachment_2341" align="aligncenter" width="1200"] Round Screw Head[/caption]
- Raised head
A Raised Head screw head is a mix between a Round Head and a Countersunk head. It is raised in the middle but not domed completely like the round head. It sinks and evens out towards the edges of the head making it more aligned with the work surfaced it is being attached to and similar to a countersunk screw head in this sense. The raised screw head, also known as an oval head, is sometimes used to add a decorative touch to a job.
[caption id="attachment_2345" align="aligncenter" width="1200"] Raised Head / Oval Head[/caption]
- Mirror screw
A Mirror Screw Head is a decorative dome head, similar to that of a Round Screw Head. The difference with a Mirror Screw to that of a Round Head is that the heads are detachable. A Mirror Screw is used for connecting mirrors to walls. They are a countersunk, flat screw with a threaded hole in the centre. Decorative domed heads are screwed into Mirror Screws.
[caption id="attachment_2347" align="aligncenter" width="1200"] Mirror head screw ( Countersunk type screws with detachable decorative dome heads)[/caption]
- Pan head
Pan head screws can look similar to a raised screw head / oval head, but they are different. A Pan Head has rounded edges, so it does not sit flat into the surface the way a countersunk does. However, a Pan Head has a flat top. This is how you can tell a pan head apart from a raised head / oval head. Pan head screws are generally used for metal work and are mainly found on self-tapping screws.
[caption id="attachment_2348" align="aligncenter" width="1200"] Pan Head Screw ( Round edges, flat top)[/caption]
- Flange head
A Flange Screw Head is one with a rim around the base of the head. This looks similar to a washer at the base of the screw head. This large rim or circular collar allows for a wider coverage area. This can be useful when covering an uneven hole. Flange heads, can also be known as Frame Bolts when in Hex form.
[caption id="attachment_2351" align="aligncenter" width="1200"] Flange Heads ( With an attached washer like rim)[/caption]
After making your decision on which screw head you will use, you will likely have another option to choose from.
Most of the above-mentioned screw heads will be divided again into two; Slotted or Crossed.
A Slotted Screw Head has a straight line running through the centre of the screw head. A Slotted Screwdriver can be used to drive or loosen these screws.
[caption id="attachment_2355" align="aligncenter" width="1200"] Slotted Screw Head[/caption]
Cross head (Philips Head)
A Cross Screw Head, or Phillips Head as it is also known, is designed with a cross shape on the head of the screw. This design was invented with the idea that less force would be required to drive or loosen the screw. A Phillips Head screwdriver can be used on these screws and also a slotted screwdriver can be used depending on the size used.
[caption id="attachment_2360" align="aligncenter" width="1200"] Cross Head / Phillips Head[/caption]
Slotted and Cross Head are the most commonly used screw heads, but there are still many more varieties available!