What’s the Difference between Bolts and Screws?

What's the Difference between Bolts and Screws

When it comes to fasteners, one of the most common questions is, “What’s the difference between bolts and screws?” While bolts and screws may look similar, there are distinct differences that set them apart. In this article, we’ll explore the bolt vs screw and screw vs bolt debate to help you understand when to use each type of fastener.

Bolts Vs. Screws

Bolts:

A bolt is a type of fastener with external threads and a head designed to be used with a nut. The primary characteristic of a bolt is that it relies on the nut to provide the necessary clamping force to hold assembled parts together securely. Bolts are not intended to create their own mating threads or hold themselves in place. Instead, they must protrude through the materials being fastened to allow the nut to engage the threads. Bolts are frequently used with washers to distribute the clamping force over a larger area.

Screws:

Screws are threaded fasteners that can have a head or be headless (e.g., set screws). Unlike bolts, screws are designed to create their own mating threads in a pre-drilled hole or, in some cases, to create their own hole as they are driven into the material. Screws do not require a nut to fasten securely; they rely on the engagement of their threads with the surrounding material to hold themselves in place. Screws are typically tightened until they are fully seated in the material and are not intended to protrude through to the opposite side, although there are exceptions.

Bolt vs Screw and Screw vs Bolt:

When deciding between a bolt vs screw or screw vs bolt, consider the following:

Bolts are used when a nut is required to secure the fastener and when access to both sides of the assembly is available.
Screws are used when the fastener needs to create its own mating threads and when access to only one side of the assembly is available.
Bolts are more often used with washers to distribute the clamping force, while screws are less frequently used with washers, except for finishing purposes.

Terminology Clarification:

At AlbanyCountyFasteners.com, we understand that the terms “bolt” and “screw” are sometimes used interchangeably in industry jargon. To help our customers find the products they need more easily, we may use these terms interchangeably on our website. However, it’s essential to understand the technical differences between bolts and screws when selecting the appropriate fastener for your project.

Key Takeaways:

Bolts are designed to be used with a nut and require access to both sides of the assembly.
Screws create their own mating threads and do not require a nut to fasten securely.
While bolts and screws have distinct differences, the terms are sometimes used interchangeably in industry jargon.
Albany County Fasteners uses both terms to help customers find the products they need more easily.

Conclusion:

Now that you understand the difference between bolts and screws, as well as the bolt vs screw and screw vs bolt debate, you can make an informed decision when choosing fasteners for your projects. Whether you need bolts, screws, or other fastening solutions, AlbanyCountyFasteners.com has a wide range of high-quality products to meet your needs. Visit our website to explore our extensive inventory and find the perfect fasteners for your next project.

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What Is Pozidriv? How Does It Differ From A Phillips Drive?

BUY POZIDRIV

What Is Pozidriv?

Pozidriv, commonly spelled incorrectly as “Pozidrive”, is an improved variation on the Phillips drive design. After the patent for the Phillips head expired, the company GKN Screws and Fasteners created the Pozidriv design.

The Pozidriv drive style was originally formed to address the largest issue Phillips heads are prone to: cam-out. Cam-out is defined as the slipping out of a drive recess that occurs when torque exceeds a certain limit. The Pozidriv drive style has the same self-centering design of a Phillips drive style but improves upon the two following factors:

Increased torque without cam-out
Greater surface contact engagement between the drive and the recess in the fastener head making it harder to slip when installed correctly

Can I Use a Pozidriv on a Phillips Screw? Or Vice-Versa?

While we at Albany County Fasteners do NOT recommend using the improper drive style on a screw, technically speaking you can. A Phillips drive style fits into a Pozidriv drive recess decently when using the right size. It’s important to note that even if the Phillips does fit snugly into the drive recess, it is still much more likely to strip or cam-out than when using the proper driver.

Alternatively, you can attempt to remove a Phillips screw with a Pozidriv drive but they do not fit into the Phillips drive recess snugly and are much more likely to slip or damage the recess during removal.

Where Are Pozidriv Screws Used?

Pozidriv screws can be used just about anywhere, although they are not nearly as popular as standard Phillips screws. Over the years, many other drive styles, such as the Torx and Robertson, have come out as being more reliable than the Phillips drive style at preventing cam-out and stripping. The Phillips drive is still extremely popular in manufacturing due to its self-centering design but is starting to lose popularity for manual applications due to other drive styles having a better design.

Benefits of the Pozidriv Drive Style

As an improvement on the Phillips drive style, the main benefit of using the Pozidrive is the increased torque without the increased risk of cam-out. Pozidriv screws can handle significantly more torque on the fastener recess than a Phillips drive can.

How Do You Identify A Pozidriv Screw?

While Phillips and Pozidriv screws look similar, Pozidriv are actually quite easy to recognize at a glance. This is due to four notches marked into the head of the Pozidriv screw that are not present in the Phillips Head Screw.

Phillips	Pozidriv

Pozidriv Screwdrivers

The Pozidriv drive style can be found in a range of sizes from 0-5. The letters PZ or PSD are usually listed before the size number (e.g. PZ3 or PSD5). ANSI standards refer to Pozidriv as a “Type IA”. The Pozidriv style can be found in two forms. Either as a Pozidriv screwdriver or as a Pozidriv screwdriver bit. We currently carry Pozidriv driver bits in several different sizes in the following Vega Bit Kits:

Pozidriv vs.

Phillips

The Pozidriv is an improvement on the Phillips drive by increasing its torque capacity without increasing the likelihood of cam-out. It also has greater surface area contact with the drive recess. This makes it less likely to strip when installed correctly. In general, you can determine if a Pozidriv screw should be used over a Phillips screw by asking the question “How much torque do I need for this installation?” If the answer is a minimal amount of torque, the Phillips drive will work, otherwise, use the Pozidriv. As an improvement on the original Phillips style, the Pozidriv style is better than the Phillips.

Torx

The Torx, or Star, drive style vastly changes the design of the drive recess. Due to the star having six points of contact (6-Lobe), the screw uses a truly radial force rather than an axial force. Phillips and Pozidriv screws use an axial force to drive the screw which is not as effective and is more likely to cause cam-out. For manual applications, Torx screws are quickly becoming the most popular choice.

ROBERTSON

The Robertson, or square, drive is quite common especially throughout Europe. The square drive offers a unique style as it must fit perfectly into the drive recess to drive properly. When it comes to Robertson vs. Pozidriv styles for manual applications, the Robertson is the winner. However, the square drive is not nearly as popular as the star drive style.

Conclusion

While the Pozidriv drive style is an improvement upon the Phillips drive style, the Phillips is still incredibly popular and does not seem to be going anywhere any time soon.

Should you be in the manufacturing field and find you are having trouble with cam-out, you may want to attempt a Pozidriv configuration. It will give you the added benefits of a reduced cam-out with a better fit into the drive recess while preserving the self-centering functionality that is a must for manufacturing. For manual applications however, both the Star and Square drives are better choices to better suit your needs.

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Self Tapping Vs. Self Drilling Screws

What Are Self Tapping Screws?

Unless you are planning on through bolting something (the process of sliding a bolt through a hole and connecting a nut to the other side to hold it in place), almost every situation involving a bolt requires a tapped hole. A tap is a tool that can be inserted into a hole after it has been drilled and creates threading for the screw to fasten into.

Self tapping screws eliminate the need for a tap by having sharp cutting threads that can tap the threading themselves while being fastened. There are two large benefits of using self tapping screws. The first is that they save time and money by eliminating the need for a tap. The second is that the resulting threading they create is much more precise and creates a tighter stronger connection. It is common to see self tapping screws used in steel and masonry materials but they can also cut into plastic or wood.

What Are Self Drilling Screws?

Self drilling screws are a commonly used variety of screw for quick drilling into both metal and wood. A self drilling screw can typically be identified by its point and flute (notch) tip. This tip acts as a drill bit for the screw making it much faster to install then having to switch between a drill bit and driver bit.

The notched area in the tip acts as a reservoir to receive wood chips or metal filings. This creates the space necessary to drill/screw the screw all the way into place.

Self Drilling Screws are almost always made out of hard steel or some metal that has been treated to increase its hardness (such as 410 stainless steel). Always make sure when using self drilling screws, the material you drill into is softer than the screw material itself. Otherwise, the screws drilling tip will dull and not cut into the material. All self drilling screws are also self tapping by the nature of how they work.

Self drilling screws are a time saver eliminating both the steps of drilling (in most cases) and tapping a hole prior to installation. This also eliminates the need for drill bits and taps and switching between them for each hole.

*While these screws are able to drill their own holes, we still recommend using a standard drill bit first especially when going through very thin wood. This step will limit the amount chance of splitting/cracking significantly.

Self Drilling Vs Self Tapping: Which Is Better?

In the world of fasteners, the usual answer for which is better comes down almost entirely to the situation the fastener is being used for. From a time saving point of view, a self drilling screw is the better choice because it can eliminate the need for a drill bit making installations a one step process. However, both have their place and it comes down to knowing which to use in the situation at hand.

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What Screws Should You Use For Building A Deck?

BUY DECK SCREWS

Building A Deck This Summer?

Having a deck in your home is a luxury many people enjoy having. Being able to sit outside and enjoy the weather or view with family and friends is an excellent way to spend nice days, especially with summer right around the corner.

If you decide to take the journey of building a deck yourself, you are going to have many questions along the way. One of the most essential points to consider is “Which screws should I use for this deck?”. We’ve heard this question before, and there are quite a few things to take into consideration.

1. What Material Should I Use?

Of all the available materials to use for your deck, the most common is stainless steel. Stainless steel deck screws offer an excellent solution due to their increased corrosion resistance. However, stainless steel can still corrode in certain situations so make sure you have the correct grade for your environment.

2. Do You Want To See The Screw Heads?

One of the biggest concerns when making your deck is choosing the correct screw head. Deck screws are usually only found in flat head varieties so they can sit flush with the wood once installed. The question remains, do you want to see the head?

If your answer is yes, then a standard stainless steel flat head deck screw will suffice. If your answer is no, then you have a few options for hiding the screw heads.

Painted Head Deck Screws – These stainless steel screws are stainless steel with painted heads to match common wood colors. They are the easiest way to hide a deck screw because they are camouflaged in plain sight. Just install them as you would any other deck screw.
Hardwood Plug Kits – These kits come with little wood corks that you can use to cover the screws. They require more work to install properly but usually leave a great result. First a countersunk hole must be made to sink the screws lower into the wood. Then an adhesive is applied to the plug and placed in the hole over the screw head. One downfall to this method is that removing them is difficult. You can also get a drill bit that can cut these plugs for you instead of buying a kit: Hardwood Plug Cutter Bit.
Ipe Clips – A third and quickly becoming a very popular option are Ipe Clips. Ipe Clips are installed between the boards of a deck hiding the screws entirely. Mostly used with Ipe wood, these clips can also be used with regular wood to help create an evenly spaced deck.

What Drive Style Should I Use?

Usually, there are three types of drive to consider here. Phillips, Square or Star drive. Although all three are decent choices, we recommend using the star drive for installations. The star drive has the least chance of slippage and cam out during installation making it the ideal choice when working with finished products where slipping out of the drive could damage the surface you are working on. In fact, on many decks built today you are more likely to see star drive screws being used.

Building a deck can be a daunting task but with the proper screws you are now one step closer to enjoying your yard and the weather this year.

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Types Of Screws | Albany County Fasteners

Types of Screws

Screws are a fastener variety that is widely used every day. They come in many shapes and sizes and all have different uses depending on the type of screw. The word screw and bolt are often used interchangeably. You will often see smaller fasteners called screws and as they get bigger they are referred to as bolts. Generally, the term screw defines any fastener that after being installed into the material holds itself into that material. A bolt is used to bolt two materials together by going through the materials and being fastened with a nut, creating a bolted joint. Consider that a machine screw needs a nut or a pre-tapped hole to install.

Screw Terminology

Screw Terminology Diagram: Drive Style, Head Type, Shank, Threading, Point, Diameter, Length, Threads Per Inch, and Thread Pitch

Material: The material that a screw is made out of. Often chosen based on environmental and structural needs.
Grade: Different compositions of a material that can change it’s qualities, making it a better choice based on environmental and structural needs.
Diameter: The thickness of the over-all screw. Determines the size of the hole that needs to be drilled into the materials.
Length: How long a screw is. This measurement can vary depending on the head style of the screw.(See Helpful Resource #2)
Threads Per Inch (TPI): Amount of thread peaks measured from peak to peak in an inch length of the fastener. Used to measure threading for imperial fasteners.
Thread Pitch: Distance between two thread peaks. Used to measure threading for metric fasteners.
Drive Style: Indicates the type of driver to be used for optimal results. For example: A Phillips head indicates a Phillips driver should be used.
Head Type: The top portion of the screw and contains the drive style. Screws have different head types based on the application they are being used for. Some make the screw flush with the installation surface while others leave the screw head exposed for a quality finish.
Shank: Refers to an unthreaded portion under the head of several types of screws. This can vary based on the length, diameter and type of the screw. The shank aids in compression and clamping force of the installaton materials, as well as, reducing the chance of breaking due to over-heating.(See Helpful Resource #1)
Threading: The portion of the fastener that has a helical shape rolled into it. Causes the screw to pull into the material and hold in place.
Point: The very tip of a screw. Depending on the type of screw, a variety of points can be available. For example: Drill Point, TEK Points.

*Note: A drive style usually has several different sizes as well. Usually indicated by a number for example: Phillips #2

Measuring Screws

Screws are measured in diameter by length. An example of an imperial screw measurement would be a #7 x 1″ deck screw. The #7 is the pre-defined diameter of the screw and the 1″ is the length of the screw. Imperial diameters range from 0 to 24 and their lengths are measured in inches. When measuring a metric screw, you use the same format of diameter by length, but both are measured using millimeters. For example, an M5 x 10M means a diameter of 5mm and a length of 10mm. It is not uncommon when dealing with screws to see the thread pitch added in as well.

Imperial	Metric
1/4″-20 x 1″	M5 x .8 x 10M

As seen above, the thread pitch is added into the middle. For imperial the 20 stands for 20 threads per inch whereas with the metric the .8 stands for .8 threads per millimeter. It is common practice to leave out the thread pitch on screws during the listing process as the pitch matters less because it does not have to match a nut. When measuring the length of screws, the head of the screw will matter. For most screw types you measure from the bottom of the head to the tip. An exception to this rule is a flat head. Always measure flat head screws from the top of the head to the point.

Screw Installation

Installing screws is a simple process. Using either a screwdriver or drill/driver with the appropriate driver bit, place even pressure on the drive recess and being spinning it. The way you will need to spin depends on the orientation of the screw threads although most are right-hand threaded (meaning spin to the right). Some screws have self-drilling points which are essentially a notched tip that allows a screw to drill into the material as it is being installed. Wood screws should always have a hole pre-drilled before installing them. Pre-drilling into wood will prevent cracks and splintering from occurring especially when working with hardwood. Self-tapping screws have sharp cutting threads that will cut deeply into the material during installation for a more secure hold.

Types of Screws

Screws are all engineered for different purposes. It is best practice to use a wood screw for wood for example because it was designed to have the optimal hold in wood applications.

Concrete Screws

Concrete Screws are easily distinguished by their blue coating which protects them in harsh conditions. They cut threads into concrete and are used to secure materials to concrete, brick or block.

Deck Screw

Deck Screws

Deck screws feature a type 17 notched point for removing chips of wood to make it easy to install in wood and composite deck materials.

Lag Screw

Lag Screws

Lag screws, commonly called lag bolts, are large wood screws with threading that extends all the way up the shaft.

Self Drilling Screws

Self-Drilling Screws

Self-drilling screws are screws with a self-drilling (TEK) point to pierce through 20 to 14-gauge metals. The higher the TEK number, the larger the drill point to pierce heavier gauge metals.

Sheet Metal Screws

Sheet metal screws have sharp cutting threads that cut into sheet metal, plastic or wood. They have a fully threaded shank and sometimes have a notched point at the tip to aid in chip removal during thread cutting.

Wood Screws

Wood screws are partially threaded with large cutting threads and a smooth shank. They are designed to slide through the top piece of wood and tightly pull all boards together. A Deck Screw is a variety of a wood screw.

Screw Drive Styles

There are many screw drive styles available depending on the type of screw being installed. The four most popular styles for screws are the following:

	SLOTTED A straight line cut into the center of the head.
	PHILLIPS The most common drive style. Shaped like a cross.
	SQUARE A square shape, resists stripping out.
	TORX / STAR / 6 LOBE Torx drive, also known as star drive, is considered the least likely to strip during a proper installation and provides a more decorative drive finish.

There are many other head types including internal hex (Allen Driven) and other more specialty heads called security heads which include spanner, Torx with pin, Philips with pin, and many more.

Screw Heads

Screw heads serve different purposes, a flat head is used to countersink the screw so nothing remains exposed. While others have more decorative or functional properties. There are many common heads on screws and each usually serves a different purpose depending on the application. Listed below are the common head types found on screws and their functions.

	Bugle Head A Bugle Head is similar to a flat head with a rounded section that will pull down drywall instead of cutting through it as it is fastened.
	Button Head A button head is a rounded head, used primarily in socket cap screws. This head sits above the installation surface.
	Button Flange The button flange head is similar to the regular button head style but with a flange or integrated washer to increase surface area during an installation.
	Fillister Head A head with a higher profile than other head styles.
	External Hex Head This head is designed to be driven by a wrench and allows for high torque installations. The head of all lag screws.
	Hex Washer Head A head that is designed to be driven by a wrench with an integrated washer or flange to increase the installation surface area. A common head for driving concrete screws due to its stronger installation points.
	No Head Exclusive to the socket set screw, lacks a head and has an internal drive in the body of the screw itself.
	Flat Head A flat head is designed to be drilled into a material until it sits flush with the installation surface.
	Oval Head Similar underside to that of a flat head screw but with a decorative rounded top. Commonly used as a finish screw in visible applications.
	Pan Head A screw with a rounded head (less so than a button or round head) and a flat bottom designed to sit directly on the installation surface.
	Pancake Head A flat topped head with a wide head to sit close to flush but also have a large surface area on the installation material for grip.
	Round Head A completely rounded head that was very popular but has become less so with the variety of heads now available.
	Truss Head With a wider installation surface area, this style is used where a lower profile is desired but a strong grip is needed.
	Modified Truss Head Similar to the truss head but with an integrated washer which increases the surface area of the head even more.

Screw Threading

Screws have both coarse and fine threading options available. Both have a place when it comes to choosing screws. Coarse thread screws tend to have a larger pitch and size relative to the diameter. This thicker threading provides more retention and gripping power (resistance to pull-out). Fine thread screws have thinner more frequent threading which prevents these screws from vibrating loose accidentally. Fine thread screws are also considered to be significantly more delicate than coarse threaded screws.

Downside Of Screws

Screws are an excellent fastener to use for a wide variety of projects but have a couple of downsides.

Shear Strength – Screws have a relatively weak shear strength. If the application will be under shear forces, bolts or nails should be used instead.
Hold – Sometimes screws loosen and it can be caused by a variety of factors.
1. Temperature Change which causes the material to expand and contract resulting in a less firm hold.
2. Vibrations cause loosening in most fasteners over-time by rotating them out of their installation.
3. Varying Weight fluctuations in load can cause screws to loosen as well by warping the material and screws themselves.

Bolts Vs. Screws

Bolts:

Screws:

Bolt vs Screw and Screw vs Bolt:

Terminology Clarification:

Key Takeaways:

Conclusion:

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What Is Pozidriv?

Can I Use a Pozidriv on a Phillips Screw? Or Vice-Versa?

Where Are Pozidriv Screws Used?

Benefits of the Pozidriv Drive Style

How Do You Identify A Pozidriv Screw?

Pozidriv Screwdrivers

Pozidriv vs.

Phillips

Torx

ROBERTSON

Conclusion

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Self Tapping Vs. Self Drilling Screws

What Are Self Tapping Screws?

What Are Self Drilling Screws?

Self Drilling Vs Self Tapping: Which Is Better?

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Building A Deck This Summer?

1. What Material Should I Use?

2. Do You Want To See The Screw Heads?

What Drive Style Should I Use?

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Types of Screws

Screw Terminology

Measuring Screws

Screw Installation

Types of Screws

Screw Drive Styles

SLOTTED

PHILLIPS

SQUARE

TORX / STAR / 6 LOBE

Screw Heads

Bugle Head

Button Head

Button Flange

Fillister Head

External Hex Head

Hex Washer Head

No Head

Flat Head

Oval Head

Pan Head

Pancake Head

Round Head

Truss Head

Modified Truss Head

Screw Threading

Downside Of Screws

Helpful Resources

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