How Does a Screw Work?
The world of screws is vast, and you’ll find no shortage of different options when you shop for screws for your next project. How does a screw work, exactly, and what are different types of screws used for? Here’s a primer on the different types of screws available to you, as well as some key information as you evaluate what types of screws will work best to meet your needs.
What Is a Screw Used For?
Screws are fasteners for all sorts of construction projects, large and small. The reason there are so many different types of screws is that there are so many different ways objects and materials need to be fastened.
Sometimes screws are classified by the material they are used to fasten. For example, you might find you need concrete screws for fastening objects to concrete, wood screws for fastening objects to wood, or drywall screws for fastening objects to drywall. No one screw or fastening could possibly serve as a one-size-fits-all solution, because there are simply too many different needs and applications for screws and fasteners.
What Are the Different Types of Screws?
Because of how many different ways there are to use screws, you’ll find there are tons of different types of screws. Here are just a few of the different kinds you’ll find when searching for the right solution:
This is just a few of the different types of screws. You may find that the screw you need is classified into one of the categories above, but it’s also categorized by its drive type (Phillips, slotted, combination, star, etc.) or by the shape of its head (oval, flat, button, round, pan, etc.). In some cases, you may find a screw is classified by a combination of terms. For example, you might find that you need a slotted flathead metal screw.
What Is the Difference Between a Self-Tapping Screw and a Normal Screw?
With most screws, you’ll need to drill a pilot hole that creates threads and helps guide the screw into a secure spot. That’s not the case with self-tapping (or self-drilling) screws. When you choose self-tapping screws, there’s no need for a pilot hole. The screw creates its own threads as it is installed.
What’s the benefit of self-tapping screws?
They save tons of time when you’re working on a significant project. For example, if you’re working to fasten objects and you need to use several dozen screws to get the job done, choosing self-tapping screws can significantly decrease the amount of time the project takes you. This is incredibly important in large construction projects where getting the project done on time is of the utmost importance.
Get the Screws You Need at All Points Fasteners
At All Points Fasteners, we work each day with service contractors to ensure they have the screws they need to deliver outstanding results. We specialize in tracking down even the most difficult-to-find fastening solutions — so our clients always have access to exactly what they need.
You find nothing but products of the highest quality in our selection, as well as affordable pricing that helps your project stay under budget.
Self-Tapping Sheet Metal Screw, Wood Screw or Lag Screw?
Even pros are confused at times on which fastener they are using on a job. They often wonder, what’s the difference between a wood screw vs. a metal screw and which do I need. When you are putting screws in to wood, then they have to be wood screws right? Well, possibly…….One good clue to spot the difference between a wood screw vs. sheet metal screw is to check underneath the head of the screws.
If the screw is fully threaded with a sharp point, you most likely have a sheet metal screw.
If the screw only is about 2/3 threaded with a smooth shank underneath the head, you are looking at a wood screw. Typically in the past, wood screws were not case-hardened like sheet metal screws and, unlike sheet metal screws, were plain steel and not plated.
But these days, there are many more options available. Some companies carry case-hardened wood screws and many are now zinc plated which gives them more protection from corrosion. The purpose of the smooth shank underneath the head was so that the two pieces of wood being fastened would draw together once the threads past through the first piece of wood.
Then there is the lag screw which is also used in wood. Frequently a customer will ask for a lag screw when, in fact, he is wanting a #14×3 self-tapping Hex Washer Head Sheet Metal Type A screw. A quick way to figure out which one you want is to ask:
1. Does it have a smooth shank underneath the head? and …
2. Does it have an attached washer on the hex head.
As you can tell from the pictures above, lag screws and sheet metal screws look quite different.
Zip Screws and Tek Screws
Self tapping screws, such as zip screws and tek screws, are perfect for jobs when you plan to connect materials that are of different varieties, such as wood to metal, metal to plastics and metal to metal. Self tapping screws are really versatile and simple to use since they will tap their own threads as you drive them into your materials, and this in turn will save you time and time equals money! There are many kinds of self tapping screws you can buy today and they each have their own purpose.
There are fundamentally two sorts of popular self tapping fasteners available, zip screws and tek screws. Type A screws are also self-tapping, as they tap their own threads, even so, they are not as popular as they normally need a pilot hole to get them started.
There are two kinds of tips for self-tapping screws and that they are the self piercing screw, also identified as zip screws, and the other is the drill bit tip, tek screw type.
Tek screws are intended for use in soft steel or other metals. The points are numbered from 1 through 5, The larger the number, the thicker metal it can go through without a pilot hole. For example, a # 5 tek point can drill a 0.5 in (12.7 mm) of steel. Contractors at times question the quality of their tek screws when the screws break, when the actual reason for breakage is the application for which they are being used. The following is a very simplified reason for heads of tek screws sometimes popping or screws twisting and breaking when drilled into steel too thick for the tek screw used. With a standard tek screw, the front of the fastener will be drilling in slower while the drill bit is drilling the pilot hole than when the threads of the tek screw catch the material being drilled. Once the threads catch, the screw will turn as fast as the TPI. In other words, if the screw is 16tpi, the screw will go in a 16th of an inch each time it turns. The problem becomes, if it is a thick piece of metal, the threads will catch before the drill bit is done drilling through the metal. The consequence is that the front of the fastener will be moving slower than the back of the screw and the screw will break. However, by having the drill bit of the screw longer up the shank of the screw and changing the threads per inch to a finer thread (24 threads per inch), the front and the back of the screw will move at the same time and the tek screws won’t break.
While self-piercing zip screws can pierce their own hole in to soft metals and create its own threads, this is usually done with thinner gauges of metal starting at 24 gauge. Needlepoint screws, are also commonly known as zip screws and are self-tapping in that they tap their own threads.
They are also sometimes referred to as self-piercing screws because they will ‘self start’ with soft metals when pressure is applied. #8 x1/2 Hex Washer Head Needlepoint screws (zip screws) have reportedly worked best when used in square duct with 30 and 28 gauge metals. Contractors state that they have better luck with a #7 needlepoint when doing round pipe with 24 and 26 gauge metals. Application is very important when choosing which fastener to use in your specific job, otherwise, the screws may not perform in the way that they were expected. Many screw ‘failures’ are actually misapplications. Although some say that they have been able to use #7 zip screws in up to 20 gauge metals, it has been our experience that when working with metal 22 gauges and thicker, drill bit tip (tek screw type) really does the job much easier.
Zip screws and tek screws are readily available to help save you time and money.