So you have finally decided to go ahead and start work on that fence project that you have been putting off for the last couple of years. Or you have decided to bite the bullet and re-roof your house yourself, or refasten your existing roofing with new screws and fasteners. Or you are doing any one of the plethora of other home improvement projects that require the purchase of various screws and fasteners.
But there are so many different ones out there, with all sorts of buzzwords and jargon attached. Like, what exactly does “S.S.T.” mean? What is the significance of something being “ACQ compatible?” What is the importance of a screw with a “Type 17 point” versus one without it? What are the different types of heads and does it really matter which head you have on your screw/fastener?
And why do screws not come with threads all the way to the head, doesn’t that mean it won’t hold two pieces of material together as tightly?
In this article we will be giving an overview of what each of the various terms means and what information you need to confidently determine which screw/fastener to buy for your project.
Terms and Definitions
The first thing to cover is the type of head on the screw/fastener. There are multiple types and names for the various screw heads, some of which are: Torx head, square drive, Phillips head, star head, and 6-lobe. At Jake Sales we only sell Torx head screws (also called star head and 6-lobe), with the exception of our Drywall Screws, which have a Phillips head and our Black Log Screws and Gray Structural Screws, which have a 5/16″ hex head.
The reason is that a Torx head screw has the maximum amount of torque that can be applied to the screw/fastener without risking stripping it out. A Torx head screw/fastener can apply almost double the amount of torque compared to a Phillips head. This ensures the tightest possible joining of the two pieces of material with the maximum amount of compression.
A Torx head also allows a fastener to be screwed in using a wide variety of angles without falling off a non magnetic head, something that a Phillips head struggles with.
Many construction fasteners come with a “knurl“, or multiple small protrusions at the top of the threads. This helps ensure that once the end of the threads are reached, the remaining smooth surface of the fastener slides easily, allowing for higher compression forces thanks to its now greatly reduced friction. This is an important feature to have, and many lesser quality screws/fasteners do not include this feature and it greatly assists with the quality of the installation. Screws/fasteners that are shorter and used for installations where a knurl would not be beneficial do not include it.
Additionally, if the screw was threaded all the way to the top, it would not be able to pull two pieces of timber together tightly, but would instead keep them the width of the threads apart all the way along the screw. The two pieces of timber would be fastened to the threads instead of each other, and would therefore not be tightly compressed together.
For this reason, all fasteners/screws carried by Jake Sales are not threaded all the way to the head.
Some fasteners come with a modified truss head, which is essentially a fixed washer directly under the head itself. This prevents the head from sinking into the material around it and also improves the compression forces, enabling a tighter join between the two pieces of material. The modified truss head is also somewhat more aesthetically pleasing once installed, as the heads will generally lie at the same approximate depth all along the the wood.
Many fasteners have what is called a “Type 17 point“, which is a small wedge cut out of one side of the point, reducing its starting size slightly and lessening the initial friction in order to help it to start screwing into wood with a vastly reduced chance of the wood splitting around the initial entry point. This also helps prevent the screw/fastener from “walking” around before it bites firmly into the material.
Construction fasteners come in several colors, one of the most predominant been gold/yellow coated zinc. These are designed to handle interior/exterior usage in a non-harsh environment (no salt spray for example) or indoor usage.
If the screw/fastener is going to be used in an environment where it will be exposed to harsh weather conditions or corrosive elements, than a screw/fastener with an exterior coating is recommend. One of the main ways these are rated by an “S.S.T.” test, or Salt Spray Test. This is a test performed on them to see how well they stand up to salt spray. Ratings on the S.S.T test start at 50 hours and go up to well over a thousand hours plus, depending on the application and environment they will be used in.
Another good rating to go off of for a screw/fastener that will be used in a harsher environment is if it is rated “ACQ compatible“, or compatible with the wood preservative ammoniacal copper quaternary. This is the most common treated wood available, with its brownish copper coloring. Wood treated with this preservative is very long lasting in an outdoor environment, but can be corrosive to metal, requiring the right screw/fastener be used that will be unaffected by the preservative.
Screw/Fastener Overview By Type
- Construction Lag Screws
- This high quality structural construction fastener is suitable for indoor or outdoor usage. It
comes with a star/torx head and is available in a variety of sizes and lengths, depending on your needs. - These are replacing the older style lag screws, due to their superior strength and easier installation (screws in with no predrilled hole required). They are heat treated and are manufactured from stronger steel than the older lag screws.
- This high quality structural construction fastener is suitable for indoor or outdoor usage. It
- Flathead Screw/Trumpet Head Screw
- This screw/fastener has nubs just under the head that help prevent small bits of wood from splintering up around it as it is inserted.
- Very common screw type
- Trim Head Screws
- This type of screw/fastener has a smaller head. Suitable for exterior or interior usage, it is
commonly used exterior corner trim, log accent trim and comes in white or bronze in order to be as invisible as possible. - Comes in bronze, bronze body with a white head, and stainless steel
- This type of screw/fastener has a smaller head. Suitable for exterior or interior usage, it is
- Tiny Head Finish Screws
- This screw/fastener has an even smaller head and, while suitable for interior or exterior usage, is
commonly found in applications such as indoor trim.
- This screw/fastener has an even smaller head and, while suitable for interior or exterior usage, is
- Cabinet Modified Truss Head/Low Profile Screws
- This screw/fastener is commonly used for applications such as installing cabinets. Its large head allows for maximum compression while its low profile gives good concealment.
- Stainless Steel Wood Screws
- These screws come in stainless steel for maximum corrosion resistance and are the best fastener for use on exteriors where there is concern about discoloration “leaching” out around the screw head as it is exposed to the elements.
- This screw also comes with the Type 17 point to reduce the risk of splintering around the insertion point.
- Black Log Screws
- These screws/fasteners use a 5/16″ hex bit instead of a torx head. They are aimed at the same application as CTX screws/fasteners, but are a slightly lower cost option for when maximum shear strength is not warranted by the application.
- They come with a thousand hour S.S.T. rating and are suitable for outdoor usage.
- They feature a shear strength of around 3500 pounds
- Gray Structural Screws
- Similar to the Black Log Screws, these screws/fasteners use a 5/16″ hex bit instead of a torx head.
- These screws/fasteners are primarily aimed at applications where it is desirable to allow the screw/fastener to flex slightly in place, such as ledger board applications and are suitable for indoor and outdoor use.
- C-Deck Screws
- These screws are ACQ compatible and have a reverse thread on top of the normal thread. This ensures that the “mushroom” that can rise around a screw as it goes into wood is flattened back down for the best appearance.
- Also sometimes called Composite Deck Screws
- Reamer Tek/Reamer Wing Screws
- Self Drilling Point
- Exterior Coated
- Used for trailers, flatbeds, or any application where wood is being attached to metal
- Bores through wood, then once the head is embedded in the steel, the “wings” snap off and the threads catch in the steel instead of the wood, ensuring a tight fit between the wood and steel
- Pocket Screws
- Modified truss head
- Type 17 point
- Used for pocket screw/pocket hole applications
- Works great with Kreg Jig® tool. Primarily used for holding together furniture/cabinets, especially corners that need to be fastened invisibly
- Cement Board Screw
- Flathead with cutting nibs on the bottom
- Comes in either sharp point or drill point
- Sharp point is used for attaching a cement board to wood
- Drill point is used in attaching a cement board to steel
- Gutter Screw
- Torx head bit used for fastening gutters to fascia
- Drywall Screws
- The most basic type of screw available
- Not weather proofed, not for exterior use
- Suitable only for interior use
- Available in coarse thread or fine thread
Further Information/Contact Us
If there are any questions you still have regarding which screw/fastener you need to buy for your project, please reach out to us at tom@jakesales.com or call us at (406) 752-5253 during our business hours of Monday-Friday, 8-4 Mountain Time