We all know that misunderstandings cost time, and money – and that jobs go much more smoothly when we’re all on the same page!
When product names are similar, this can lead to confusion, as you order the wrong item and then have to replace it!
Construction projects often face unavoidable delays and complications, but misordering is avoidable.
Making sure to order the materials you need will save you money, and save you time. Self-tapping and self-drilling screws are materials which often succumb to this fate – probably because self-drilling screws are actually a subcategory of self-tapping screws! Both are used in general construction, as well as in metal work specifically, but they aren’t interchangeable! That’s why we’ve written this blog post, to help you understand the crucial differences between self-tapping and self-driving screws.
Let’s go through the crucial differences between them so that you can ensure you’re ordering the right materials for your project.
What is a self-tapping screw?
Self-tapping screws are different from ‘normal’ screws. That is because they have the ability to tap their own threads when inserted into a material, for example, metal, wood, or plastic. They are usually split into two further varieties – thread tapping, and thread forming.
What’s a thread-forming screw?
A thread-forming screw will create a thread when it’s inserted into a material, in its own specific thread pattern. Because they tap their own threads when inserted, they do not require a pilot hole to be created before insertion.
We’ll focus on thread-tapping self-tapping screws here.
A self-tapping screw can tap a thread into the material it is screwed into. Self-tapping screws are used on all sorts of materials, including wood, metal, and brick. They are commonly used when you are only able to access one side of the material you’re working on but need to attach two pieces of material. A screw and bolt would be more efficient when both sides are accessible, but self-tapping screws are useful for disassembling and reassembling furniture, for example, as they will insert into the same thread they have been removed from.
Self-tapping screws are known by various names, including sheet metal screws, metal screws, tapping screws or tapper screws.
Self-tapping screws (thread tapping) CANNOT drill through the material they are used on.
These types of screws need a hole to enter before utilisation. That means pre-drilling (or pre-punching) a ‘pilot hole’ through the materials you’re attaching, before using your self-tapping screw.
Creating a pilot hole is simple – it simply means using a drill bit that is slightly smaller than the screw you will use, to create a hole.
Once you’ve made your pilot hole, the threads of the screw on a self-tapping screw will tap into the materials you’re joining together.
Self-tapping screws have different tips/points
Self-tapping screws come in a variety of different tip shapes. They are defined as thread-forming, thread-cutting, or thread-rolling, and are shaped as pointed, blunt, or flat.
- Pointed self-tapping screws are thread-cutting. This means they will tap and create threads in a pre-drilled pilot hole.
- Flat self-tapping screws are thread-rolling. This means they extrude thread when inserted, and there is no clearance between the screw and the material it is inserted into.
How to choose the right self-tapping screw
The right self-tapping screw depends on the application. What material will the screw be used on? They are different types of self-tapping screws which will work best on specific materials, from wood to metal or plastic. You must also consider the size and length of the screw, as well as the level of torque (or tightening force) that you require in your application.
How to use self-tapping screws
They are generally easy to use and can be utilised with both power drills and screwdrivers. You must be aware, however, that overtightening can cause the screw to strip its threads, and this will greatly reduce its staying power. Ensuring that the pilot hole is the correct size is also crucial – too big and the screw won’t thread properly and will become loose. Too small, and the screw may break, or the materials you’re joining may crack. Proper thread formation is integral to a self-tapping screw’s strength and efficiency.
What materials can a self-tapping screw be used on?
Self-tapping screws work across many materials and applications, as mentioned above, but it’s important to choose the best one for your specific job. They can be used on various types of plastics and plastic mixes, from plywood to fibreglass to polycarbonate. They can also be used on metals, and cast or forged materials such as aluminium, iron, brass or bronze.
What are self-tapping screws used for
As mentioned above, they are the perfect screw choice when you cannot access the rear of the materials you are joining. Such applications include fastening together sections of aluminium, inserting screws into plastic housings, and attaching metal brackets onto wood.
Benefits of self-tapping screws
Self-tapping screws are really versatile and useful in a range of applications. With a self-tapping screw, you eliminate the need to pre-tap the materials you’re joining. Pre-tapping means creating a thread through the materials for the screws to bind. Getting rid of this additional step saves time, and therefore labour costs. It also allows for a wider range of applications, as it can be used on materials which are too fragile to withstand pre-tapping.
Make sure to consider size, length, materials you wish to join, and the thread pattern of the screw, as well as the exact punch or drill hole, to ensure the screw is most efficient. Following proper installation, a self-tapping screw will provide a reliable, secure hold.
Similarities between self-drilling screws and self-tapping screws
The most crucial difference between them is that self-tapping screws require a pilot hole, whereas self-drilling ones don’t. These screws can drill, tap, and fasten all at once. But what are the similarities between them?
- Both can tap their own threads through the material, negating the need for pre-tapping.
- Both are ideal for application in metal building construction.
- Both can be used to fasten metal, plastic, and aluminium components.
What is a self-drilling screw?
As mentioned above, self-drilling screws take the self-tapping screw one step further, by also drilling at the same time. They don’t require you to pre-punch a pilot hole.
Self-drilling screws are often known by their brand name – Tek Screws. Self-drilling screws can be recognised by their point, which looks like a drill bit. Drill points come in numbers 1-5. The quantity of steel they can drill through increases as the number increases, the bigger the number, the bigger the hole.
When to use self-drilling screws:
You can use self-drilling screws in similar applications as self-tapping screws, for example attaching wood to metal or metal to metal. They are most successful at attaching lighter, less dense materials.
Self-drilling screws are brilliant for HVAC applications and light gauge metal assemblies, cladding, metal roofing, steel framing, and metal building. Obviously, they’re useful across a range of construction tasks, but they do have more specialised applications than a self-tapping screw does.
Confast delivers high-quality fastening and fixing supplies across the UK and Ireland. Get in touch for your fixing requirements today.