Are you sick of stripping screws? Maybe you’ve ruined your last project and now you’re wondering which screw head is the strongest? In this article, we’ll dive into what makes a screw-head strong and why all screws are not super strong.
The strongest screw heads are typically star-shaped, Torx bits, or square-shaped, Roberts bits. However, a well-fitted Philips head is also strong. Keep in mind that it comes down to more than the type of screw head, it’s also the materials used to make the screw as well as the fit of the drill bit.
Below, we’ll look at what makes a screw strong. Then, we’ll talk about why all screw heads aren’t strong (and why they are this way on purpose).
What Makes a Screw Head Strong?
In the next sections, we’ll go over all the different things that affect the strength of the screw. As you’ll see, there is much more at play than just the design of the screw head, though you’ll see that this does come into play.
Also, we may touch on some of the weakest screw heads, and we’ll discuss why they are made to be that way.
Here are several things that affect the strength of a screw head:
- The type of screw head
- The material of the screw
- The bit used (material and hardness)
- The fit of the drill bit
- The torque of the drill
Let’s look at these things in more depth.
How a Screw Head Affects Strength
The first thing we will look at is how the shape and design of the screw head affects the strength. However, the reason we won’t stop here is that the design of the screw head does not tell the whole story.
This is an issue, because if someone says that star-shaped bits are the strongest, without pointing out the nuances, then someone might buy a bunch of star-shaped bits hoping for strength, but ending up with unsatisfactory results.
In general, the Torx and the Roberts (Star and square-shaped) bits are known to be two of the strongest screw heads. Why is this? For the star-shaped bits, the multiple points of contact lead to a very strip-resistant screw head. Anyone who has used a star-shaped bit knows that they lock into place and seldom strip.
For the square-shaped screw heads, the strength is found in the snugness of the fit, similar to hex wrenches. One thing about the square-shaped bit – the drill bit itself usually gets gradually wider closer to the base. This gradual widening serves to lock the bit into place.
We should mention that a well-fitted Philips screw is also quite strong. However, getting a good fit is the trouble. The main issue with Philips bits is that it is very easy, and sometimes very tempting, to use the wrong-sized bit.
How the Material of the Screw Affects Strength
Now let’s talk about how the material of the screw affects its strength of the screw. Why is this important? Well, we’ve said that, in general, a star-shaped bit is stronger than a Philips head bit. But what if the star-shaped bit used a soft, cheap material? Is it still stronger?
Probably not. In general, a quality screw that’s made to resist stripping will win the day, even if it’s not known to be the “strongest’ bit shape.
Keep in mind, some quality screws will be made with softer metal than others. This can be done for different reasons.
First, it could be that the material they are screwing into requires a softer screw, that won’t accidentally break or crack the material – you might run into this when drilling into different types of glass.
Second, though it’s a bit confusing, softer metals are typically more resistant to breaking than harder metals. In this case, the softer screws might be more likely to strip, but less likely to break when under structural pressure. These are all things to keep in mind when purchasing and using screws.
Let’s not forget a key component – the drill bit.
How the Drill Bit Effects Screw Strength
The drill bit is easy to overlook when talking about the strength of screws. However, people must realize that a properly fitting drill bit is the key to a strong screw head (and to avoid stripping).
It doesn’t matter if you paid a million dollars for diamond-coated screws – if you don’t have the right drill bit, one that fits perfectly, you are in danger of stripping the screws. Always ensure that your drill bits match perfectly to the screw. This is easier to do with screws that take Star-shaped or square-shaped bits, as there is really only one bit that will fit. On the other hand, it’s very easy to use the wrong bit on a Philips screw.
Second, pay attention to the material and the hardness of the bit. Some drill bits will be cheaply made and will crack under too much torque. If a drill bit cracks, it’s useless. However, if the drill bit is too soft, there is a risk of it becoming deformed – essentially becoming stripped along with the screws. Now let’s talk about the drill itself, which is another crucial component.
The Torque of the Drill and Screw Strength
The torque of the drill as it relates to the drill bit and the screw is of utmost importance. Unfortunately, many people don’t consider the dangers of using a powered drill – they just think it’s faster, so they grab it and start drilling away. However, this hasty action often results in stripped screws, stripped pilot holes, and broken bits. Let’s talk about how to avoid this.
Always consider the torque setting on your drill. Also, keep in mind that a hammer drill or an impact driver (these are different things), will usually be much harder on screws. Don’t be surprised if hammer drills and impact drivers crack drill bits and strip screws – especially if they are improperly used.
For rugged projects, like placing planks on a wooden deck, you can probably get away with using the highest torque on your drill – as long as you are using high-quality screws and drill bits.
However, if you’re just doing everyday tasks, like trying to place a screw to hang a picture, or you’re working on a more delicate project, then you have two options. First, you can turn the torque setting on the drill way down (the torque setting is the numbers around the end of the drill), this will stop the drill from applying massive amounts of torque.
The second thing you can do: use a hand screwdriver or use a small, low-powered drill. This will ensure that you don’t accidentally strip a screw or crack the drill bit.
Now, before we go, let’s talk about why all screws aren’t made with high-strength screw heads.
Why Aren’t All Screws Strong? (The Point of Weaker Screw Heads)
Why are some screws so weak? Well, the obvious answer is that they are low quality. However, there is more to the story than just this. Let’s talk about a few reasons some screw heads aren’t made with the strongest design (Torx, or Roberts).
Reasons for “weaker” screw heads:
- Small projects
Let’s look at this in more depth.
Versatility and Weaker Screw Heads
It’s true, Philips head and flathead (or slotted) screws are not known for their strength, but they are known for their versatility. This means that you can unscrew and screw them with many different objects. This is really helpful when you’re just using screws for small projects around the house.
The flathead, for example, can be unscrewed with many different items – you don’t need one specific-sized screwdriver as you do with a star-shaped bit. Sometimes you can unscrew slotted screws with a knife, a coin, or a fingernail.
The same is true for a Philips head screw. Yes, you usually need a Philips head screwdriver (though some Philips’s heads are designed to accept a flathead screwdriver), but you usually only need one type of Philips head screwdriver. This makes it easy for manufacturers, as they don’t need to worry about providing screwdrivers for everything they sell.
Small Projects and Weaker Screws
When using screws for certain items, such as plastic objects, it is in the interest of the person to have weaker screws. Here’s why.
Stronger, harder screws would be much more likely to strip or crack the plastic. However, weaker, softer screws will strip before they crack the plastic – instead of replacing the whole item, you just need to replace the screw.
In this way, softer “weaker” screws can act like a built-in safety mechanism, ensuring they aren’t overtightened.
Final Words on the Strongest Type of Screw Head
What’s the strongest screw head? It’s probably the Torx or the Roberts. But that’s not the whole story. Be sure to factor in the fit of the drill bit, the torque of the drill, and the quality of the screws themselves. All these things will have an effect on the strength of the screw head.