Considering that both screws and nails are widely used for connecting pieces of wood, to a layman they might seem interchangeable. And, while that is true to a certain extent, there are certain situations where one is better over the other.
In this article, I’ll take a look at what the differences between screws and nails are as well as what are their advantages and disadvantages. I’ll also talk about what applications screws are better for, and in which cases, you should use nails if possible.
Screws and Nails: The Basics
Both screws and nails are fasteners. However, that – and the fact that they both consist of a shank with a head on one end of it – is where the similarities between the two end.
So, let’s start by looking at what exactly makes a screw a screw – and a nail a nail.
Considering that we are comparing them with nails in this article, let’s focus on a specific type of screws – wood screws.
As their name suggests, wood screws are fasteners with a thread that cuts into the piece of wood it is being driven into. Screws are driven by turning – either manually with a screwdriver or using an impact driver.
They can be made of a variety of materials. However, most of them are made out of steel. Compared to some other types of screws, wood screws have sharper tips which make it easier for them to initially penetrate the wood.
Shorter ones have a shank that’s threaded throughout while longer ones oftentimes have an unthreaded portion towards their head. The unthreaded part prevents the screw from “grabbing” the top board that you are screwing through, and thus allows for the two pieces you are working with to be joined tightly without a gap.
Wood screw heads most often come with Phillips drive, but ones with a slotted drive are fairly common as well. The most commonly used wood screws have flat heads, but they are available with pan and oval heads as well.
Nails, just like wood screws, are fasteners that are most often used to join two separate pieces of wood. That said, sometimes, they are also used as hangers and similar where part of the nail sticks out of the material it is being driven into.
Generally, they are made of metal. Nails have a long unthreaded shank with a sharp tip and a (most often) round flat head on their other end. Headless nails are available as well.
Since nails don’t have a thread, they have to be driven into the workpieces by applying force along their length. That is most often done manually with a hammer or using a nail gun.
Screws vs. Nails: Which Are Better?
As mentioned in the introduction, the ideal fastener to use – whether it’s screws, nails, or something else – will depend on your exact situation. The pros and cons listed below will help you analyze your own situation and choose the better one for you.
The Pros and Cons of Screws
Let’s start with the three main advantages of screws:
- Stronger holding ability: Screws can hold two pieces of wood together very strongly – they have good tensile strength. Even more so if used in conjunction with wood glue.
- Safer to drive with a power tool: A nail gun can be a fairly dangerous tool. On the other hand, an impact driver is one of the safer power tools. Not only that, but it is also owned by many more people than a nail gun.
- Easy to unfasten: When it comes to disconnecting the pieces you joined, screws are much better as you can simply unscrew them.
The disadvantages of screws include:
- Cannot withstand much twisting: While, as mentioned in the pros, screws have good tensile strength, they can break easily when twisted.
- Can split wood more easily: Because of their thread, a screw will be generally thicker than a nail with similar properties. As such, it will also make it easier to split the wood you are driving it into.
- Takes longer to drive: Both when driven manually, as well as using an impact driver, it takes a fair amount of time to tighten a screw.
- Can get stripped: When used improperly, screws can get damaged – stripped. While nails can get damaged too, removing a damaged screw can be much more frustrating.
- Relatively expensive: Even though the difference is minimal, screws are generally more expensive than nails as they are more difficult to manufacture.
The Pros and Cons of Nails
To get a quick list of the pros and cons of nails, you can simply take the list related to screws I wrote out above, and reverse it. However, let’s look into it in a bit more details.
Let’s start with the advantages of nails:
- Can withstand a lot of twisting: Because of their simpler construction, you can bend and twist a nail many more times than you can a screw without breaking it.
- Can be driven very fast: If you have a pneumatic nail gun, it literally takes a split of a second to drive a nail. That’s much faster compared to tightening a screw – even when using an impact driver.
- More difficult to tamper: Anyone with a screwdriver can remove a screw. Removing a nail, on the other hand, is much more difficult.
And now, let’s take a brief look at the disadvantages of nails:
- Difficult to remove: While it can be an advantage to a certain extent, it also makes it difficult to redo things. Removing a nail is especially difficult if you want to do so without damaging the wood it has been driven in.
- Driven by force against the workpiece: Unlike screws which are driven by turning around their axis, nails are driven by applying force in the direction of the workpiece. As such, they are not ideal for “delicate” applications.
- Cannot be driven with precision: Sometimes, you might want a part of the fastener to be sticking out – whether to serve as a hook or something else. It’s much easier to control the depth to which a screw is driven than that of a nail.
Finally, let’s take a look at a couple of frequently encountered situations where you have a choice between using screws and nails.
Screws vs. Nails for Framing
When it comes to building frames and structures that are meant to provide considerable support, nails are by far the preferred option due to the fact that they are more difficult to snap.
In fact, most rules and regulations are designed with nails in mind – defining the minimum size of nails to be used, the maximum spacing, the patterns to drive them in, and so on.
In either case, before deciding on whether to use screws or nails – and even what size to use – for a major framing project, consult the local regulations.
Screws vs. Nails Building a Deck
If you are planning to build yourself a wood deck, you have three options – use only screws, only nails, or a mix of both. While most often people opt for one of the first two, especially for using only screws, I recommend using both screws and nails – each in different parts of the deck.
Use nails to connect your deck framing to the joists holding it up as that’s the part that will encounter the most “twisting” force.
Use screws for securing deck boards to the frame. That way, you will be able to attach them tightly. And, if you will need to replace one of the boars for one reason or another, it will be easier to just unscrew it rather than having to pull nails out.
Screws vs. Nails for Building a Fence
When deciding what kind of fasteners to use for building a wooden fence, you cannot go wrong with either screws or nails. It’s mostly a matter of preference.
If you decide to use nails, you might be able to build the fence a bit quicker, and it might be able to withstand a bit more in terms of people leaning against it and thus applying a twisting force to the joints.
At the same time, though, using screws will allow you to replace pickets more easily.
As such, you might want to consider an approach similar to building a wood deck – building the frame using nails, but attaching the individual pickets with screws.
Screws vs. Nails for Building Furniture
When building furniture, you can use – with some limitations – both screws and nails. There will also be times when other methods of joining two pieces of wood, using dowels, for example, will work better.
The main rule to follow is that if you are building a piece of furniture out of plywood, blockboard, or other similar “composite” materials, you should use screws.
Otherwise – if you are building something out of solid pieces of wood – you should consider the advantages and disadvantages of both that I listed above and decide on which suits your application the best.
In terms of how they work, the main difference between screws and nails is the way they are driven into the workpiece. While screws have a thread that cuts into the wood, nails have a threadless shank that is driven into the wood with sheer force.
Because of the difference in design, both of them also have their own advantages and disadvantages. The main advantage of nails is their resistance to twisting – i.e. they won’t snap.
On the other hand, screws have higher tensile strength and can also be removed easily.
All in all, whether you should use screws or nails for your project will depend on what you are working on. Use the list of pros and cons above to determine which one is better for your specific use. Alternatively, refer to the practical applications I talk about in the previous section.