If you’ve ever tackled a DIY project, chances are you need some sort of screw to complete it. Most project plans often say things like “you’ll need 1.25” wood screws” (if they even specify the screws you need at all).
But if you go down the aisles of Lowe’s or Home Depot, it can quickly become overwhelming. Not only is there a whole aisle of different types of screws, but there’s still a whole section for “wood screws.”
In today’s post we’re going to talk about the different types of wood screws available and how to choose the right one for your project. Please note that I said wood screws. If you’re doing a project with material other than wood, like drywalling, you’ll want to get a screw specific to that.
I’ll give you a lot more details in the rest of the post, but if you’re looking for a quick answer, here it is: I generally recommend using #8 wood screws for DIY furniture projects. We like the PowerPro brand. They are more expensive, but they don’t require pre-drilling and the star head resists stripping. For length, we generally use 1.25” screws for ¾” wood and 2.5” screws for 1.5” wood. That said, we almost always countersink our wood screws, so they end up sitting further into the second piece of wood. If you aren’t countersinking, you may consider longer screws, particularly when using 3/4″.
Parts of a Wood Screw
First let’s get familiar with the terminology. Here’s a breakdown of the anatomy of a screw:
Choosing the Right Length
Arguably the most important thing you need to get right when selecting a screw is choosing the correct length. There are two common “rules” you can follow for this that will get you in the right ballpark.
We personally use rules #1 because it works in pretty much every situation, but we’re sharing rule #2 here as well because sometimes it can be a bit easier to remember. When we get to rule #2, we’ll share the instance where you should exercise caution.
“Rule” #1: The screw should go at least halfway through the thickness of the board you’re drilling into.
This is the rule I usually stick with because it accounts for all orientations of boards. You can attach boards perpendicular to one another or stack them on top of each other.
Example #1: if you are securing a 1x board to a 2x board, your screw will be 1.5” long. ¾” to account for the thickness of the 1x board + ¾” to go halfway into the 2x board.
You can also opt for a 2” screw for even more security. This is long enough to meet the minimum halfway rule, but not too long where you risk poking out the bottom if the boards on stacked on one another.
Example #2: if you are securing (2) 1x boards on top of each other, your screw will be 1.25” long. ¾” to account for the thickness of the top 1x board + ½” to go slightly more than halfway into the second 1x board.
“Rule” #2: The screw should be 2x the thickness of the wood you’re drilling through.
Let’s look at the same examples as we did above.
If you are securing a 1x board to a 2x board, your screw will be 1.5” long, which you get by doubling ¾”.
The rule works if you are securing a thinner board to a thicker board or securing two boards that are the same thickness perpendicularly to one another. It falls apart however if you ever need to attach two boards of the same thickness on top of one another.
If you stack (2) 1x boards on top of each other, they are 1.5” thick. If you choose a 1.5” screw, you’ll likely experience some tearout on the backside of the second piece of wood. You are also likely to potentially poke through the backside of the second piece of wood if you accidentally screw in just a hair too far.
If you don’t want to remember a rule and just want a guideline, here’s what we use.
When working with 1x lumber (aka ¾” thick wood), you’ll generally use 1.25-2” screws. If you’re stacking boards on top of one another, 1.25″ is best. If installing perpendicularly to one another, 1.5 – 2″ is best. When working with 2x lumber (1.5” actual thickness), you’ll generally use 2.5-3” screws. If using multiple thicknesses of wood, you’ll want to refer back to one of the rules to get the best size.
Choosing the Right Gauge
When buying screws, you’ll often see them labeled something like this: #8 x 1.25” wood screws.
The second number is the length of the screw. The first number refers to the gauge, or thickness, of the screw. The larger the number, the bigger the screw.
#8 screws are the most common and can be used for a wide variety of projects, including most DIY furniture. When in doubt, choose #8. If you’re using longer screws and don’t see the option for #8, choose #10.
#4 screws are good for dainty hinges. #6 is great for drawer slides and other hinges. #8 can be used for most DIY furniture projects, cabinets, and other general construction. #10 is great for outdoor projects and heavier duty projects.
Choosing the Right Material
Screws come in a variety of different materials. The most common materials are zinc, stainless steel, and epoxy coated.
Zinc screws are generally the cheapest and are great for interior projects.
Stainless steel is a popular option for exterior projects as they are very resistant to corrosion.
Epoxy-coated screws are also a great option for exterior projects as well. Our favorite brand of screws, PowerPro, use epoxy-coated screws for their exterior screws.
If you’re working with pocket holes, Kreg Tool offers a special “Blue-Kote” screw that was designed for use in exterior projects and treated wood. It’s a screw that’s been protected with an additional coating to prevent the screw from rusting.
You don’t need to spend much time analyzing the material of the screw. The main thing you need to know is if it is for interior or exterior use. Most packaging will explicitly say if it’s compatible for exterior use.
You can always use exterior screws on interior projects, but most people opt to use zinc for interior projects since they are generally cheaper. That said, when working on an exterior project, you need to use exterior screws. Don’t be trying to use your cheap interior screws outdoors or they are likely to corrode over time!
This section is going to be quick because drive type is mostly a matter of personal preference. The only reason I decided to include it was to provide a warning.
Many wood screws have Phillip’s head drives meaning you can use a typical drill bit or Phillip’s screw driver to install the screw.
If you choose a screw that has a different type of drive, you will need to get the accompanying drill bit for it. Most screws (like PowerPro brand) will include the required drill bit if it’s a specialty drive, but you may need to purchase the proper drill bit separately if getting square drives (common for pocket holes) or something like these polymer screws we used on our DIY hammock stand.
If you’re prone to stripping screws, we highly recommend switching from the standard Philip’s head to screws with a star head. The star head makes it way less likely to strip–we’ve never had an issue with screws stripping when using PowerPro screws!
Types of Wood Screws
Now that we’ve covered some of the different characteristics of screws, let’s talk about different types of wood screws. There are general purpose wood screws that can be used for a wide variety of wood projects, but there are also some specialty screws that are better fit for a specific job.
General Purpose Wood Screws
These are what you will use on the majority of DIY woodworking projects (when not using pocket hole screws). There are a couple of different head shapes for these screws. The most common are a flat head or a round head.
The flat head screws often have a cone shape underneath the head. This allows the screw head to sink flush or just below the surface of the wood. This is helpful if you want to cover your screw heads or don’t want the screws to stick out from the surface.
The other common option is a round head. We generally use these when installing things like drawer slides where we don’t want the screw to go too far in.
You can use either type for your projects–it’s mostly a matter of personal preference for the look.
Pocket Hole Screws
People also ask me if they can use regular wood screws for pocket holes. Pocket hole screws are slightly more expensive, but they were specifically designed for pocket holes.
The first difference is the head of the screw. The Kreg screw is designed to stop the screw from going any further once it reaches the end of the pocket hole. The regular screw has more of a cone underneath the flat head which is meant to help it sink into the wood so that it sits flush or just below the surface of the wood.
The second difference is the self-tapping tip of the Kreg screw. Typically, you need to pre-drill before driving a screw, but the angle and position of the pocket hole makes it pretty much impossible to know the exact location to properly pre-drill with pocket holes. The self-tapping tip of a Kreg Screw helps eliminate the need for pre-drilling and prevents the wood from splitting when drilled into.
Kreg screws come in two main types: course thread and fine thread. Hardwoods like oak will require fine thread screws while course thread is used on any plywood or softwoods like pine.
As the name implies, deck screws are what you want to use when installing a deck. These screws are specially designed to resist rust and corrosion, ensuring your project withstands the elements. Deck screws typically have a coarse thread and a flat or star-shaped head for increased holding power.
Cabinet Mounting Screws
When mounting cabinets to the wall, you’ll want to opt for cabinet mounting screws over traditional wood screws. The main difference for this is the head of the screw. The head of cabinet mounting screws are wider and sometimes include an integrated washer. This helps provide an ultra-strong hold without the risk of accidentally countersinking into the back of the cabinet.
This is a screw we never personally use because we do not build with MDF, but I wanted to include it here as well. When building with particleboard or MDF, you’ll want to use confirmat screws. They have deep, coarse threads to provide a secure connection, even in these weaker materials.
How to Choose the Right Wood Screw for Your Project Conclusion
When heading to the store to choose the right wood screw for your next project, you’ll want to keep a few things in mind: the length, the gauge, the material, and whether or not you need a specialty screw.
For length, we generally use 1.25” screws when working with ¾” wood and 2.5” screws for 1.5” wood. For gauge, #8 screws are the most universal. For material, zinc is great for interior projects while stainless steel and epoxy coated are great for exterior projects.
If you’re using your screw for a very specific purpose like mounting a cabinet, building a deck, or using pocket holes consider getting a screw specifically designed for that purpose.