When it comes to picking between a fully or partially threaded screw, you’ll know that it’s normally one or the other.
Both have their benefits and flaws, so it’s important that whatever one you choose is the right one for the project at hand.
But what exactly do they do? What makes them different, besides the obvious? What do they do differently?
That’s what we’re going to answer for you in this article. Multifix supplies a wide range of screws, so we will take a look at what both of them do, what their pros and cons are and how they differ.
Come the end of the article, you’ll have everything you need to know which screw is right for your upcoming project!
Fully threaded vs. partially threaded – what are the key differences?
As you can tell by the name, the main difference is the screw itself. A fully-threaded screw will have a thread going all the way to the tip of the screw head. It is also made up of three parts – the head, shaft and tip.
Meanwhile, a partially threaded screw will have a thread about half the length of the screw. The remaining part of the screw is a completely smooth section, which helps with clamping (more on that later).
Like the fully-threaded screw, it is made up of a head, shaft and tip, but the shaft is both threaded and unthreaded.
Pros of the fully-threaded screw
With a fully-threaded screw, you can drill straight into the material and the surface it’s being drilled into won’t split. When it comes to working with wood, this is especially important to note.
This is down to the way the screw is designed and in addition, they generally come with a self-tapping tip, which ensures the hold.
Because the thread goes all the way to the top, fully-threaded screws are a one-and-done type of screw, in that it shouldn’t come loose in the future.
Pros of the partially threaded screw
What makes a partially threaded screw so useful is that it guarantees a better fit. Basically, the threaded part of the screw only goes into the bottom piece, so it pulls it in tighter and clamps it down better.
This is made possible because of the smooth part of the screw. As there is only part of the screw that has a thread, the thread hones in on the bottom piece, with the smooth part flowing through to keep things tight.
Effectively having a level of auto-clamping is a huge boost. Sometimes, it’s just not possible to be able to clamp two pieces of material together with a vice.
Cons of fully-threaded screw
The main con to a fully-threaded screw is that it is very prone to jacking. Jacking is when the threads in both materials become separated. The thread in the top part of the material holds it up, thus making it impossible to clamp properly.
Unless both materials are physically clamped down with a vice, there is a high risk that a fully-threaded screw will cause jacking.
As mentioned above, sometimes it isn’t easy or possible to have two materials physically clamped together. If you’re working in a tight space, this is something you need to consider.
Cons of a partially threaded screw
Getting sizing right is key when it comes to partially threaded screws as if you get it wrong, you run the risk of splitting the material.
If any part of the smooth side of the screw goes into the material you’re drilling into, the top material will likely bulge or split. This is because the screw would’ve gone too deep.
As such, you’ll have to make sure that the screw is measured properly before use, which can be a drawback depending on what materials you’re working with.
Choosing between the two
There are clear differences and strengths between both screws, but whatever one you pick is going to depend on what project you’re working on.
If you’ve got a lot of space and can use a vice to secure materials together, then a fully-threaded screw won’t let you down. You can also provide a lot of long-term security by having one fitted properly, too.
If things are a bit tighter space-wise, or if you just want a better fit, then partially-threaded screws should be your go-to.
Just be sure to make sure that your partially threaded screws are the right size before you use them, if you so choose to go down that route.
If you would like some further information on the type of screws we provide, or some extra clarification, you can reach our expert team here. Equally, if you need something now, you can see the variety of screws we stock at Multifix here.