What type of screw do I use for what job?
1. Choose the right size
The thickness of the material determines how long the screw you'll be using is. The rule of thumb is that the length of the screw should be 2.5x the thickness of the material that needs to be screwed down. So if you're screwing down a 15-millimeter shelf, you'll need to use a screw that's 37.5 millimeters in length. A screws dimensions are always indicated as length of the screw x diameter of the head.
2. Choose the right head shape
There are a lot of things you can pay attention to when choosing the right screw, but 1 of them is the shape of the head. Depending on the job you're planning to do, you'll choose a screw with a certain head shape. Does it need to look appealing, or is it more important that the connection should be very strong? Useful to know before screwing the screw down into the material.
If you're going to connect wooden components to each other, use a flat-head screw. The screw will sink flush with the wood, which not only looks pretty, it's also safe because no part of the screw is sticking out of the surface any longer. In softer types of wood such as pine wood, you'll be able to screw the flathead screw down easily, without pre-drilling. With harder types of wood, pre-drilling is recommended. Examples of jobs you can get done using a flathead screw include: fastening plates to stairs, making a wooden bench for in the garden, or screwing a footbridge together.
If you're going to connect metal or stainless steel to wood, a cylinder head screw is a clever choice. For example when fastening metal mounts or anchors. This type of screw is also recommended in combination with a plug. The screw part starts immediately below the head, which means this screw won't sink like a flat head screw does. Pre-drilling isn't necessary when screwing down a cylinder head screw.
As the name implies, this type of screw has a spherical head, meaning the head will always stay visible above the surface. The screw thread on this type of screws doesn't keep going all the way to the head, but the underside of the head will lie tightly against the material after being screwed down. Because of this, there's no need to make a countersink hole to let the screw sink into. The spherical head looks pretty on, for example, furniture or other workpieces for decorative ends. Usually, spherical head screws have slotted heads.
If you're making your own furniture or decorative work pieces, grab a lens head screw to connect components to each other as neatly as possible. Because the part below the head is slanted, the screw will partially sink into the wood. Combined with the bulging top, this provides an elegant finish, for example for baseboards, laths, or wooden frames.
You'll need a countersunk screw if you're going to make constructions with heavy wooden girders, such as a porch or garden house. The flat disk on the underside of the head provides a larger clamping face, ensuring heavier materials will stay firmly attached. More technically speaking: it;ll increase your load-bearing capacity. For the same reason, you won't need as many mounting points.
3. Choose the right screwdriver bit
If you use the wrong bit to screw in a screw, chances are you might damage the screw. For that reason, take a good look at the drive on the screw head, in order to choose the right tools for it. The most common types of cutouts in the screw head are the cross, Pozidriv, slot, torx, and hex. Want to know more about the screw drive? In the next article, we'll take an in-depth look at this.