Should I Use: Coarse Thread Vs. Fine Thread Fasteners

Coarse Thread Vs. Fine Thread Fasteners

Which One Should I Use?

Coarse thread vs. fine thread fasteners is one of the most common questions in the industry. Surprisingly, many people don’t know that there are some significant trade-offs to the type of threading you choose for a project. Each kind of threading has some benefits that the other lacks.

Threading are uniform ridges of varying height and width (from fastener to fastener) that wrap around a cylinder. This helical shaped threading can be either wide set and deep which are considered coarse thread while a more narrow helical shape with shallow ridges is considered to be fine thread. Both have benefits the other lacks, so which one should you choose?

Coarse Thread

Coarse thread fasteners are an excellent choice for most applications. Commonly chosen for construction simply because their threading can be lightly damaged and still work effectively. Coarse threading allows for more material to sit between these threads as they are installed. Due to this, it is harder for coarse threaded fasteners to strip or cross thread. Their extra tolerance allows for nicks or marring to occur on the edges of the threading without inhibiting the ability to fasten them.

Coarse threading is also much less likely to gall then fine threading. Fine threading requires many more turns per inch which generates more friction. Excess friction dramatically increases the chance of galling in fasteners. Regardless we recommend using an anti-seize solution especially on stainless steel fasteners. Coarse threading also handles obstructions (such as dirt) in the threading better. They can be fastened even when not fully clean.

Fine Thread

While coarse threading fasteners are better suited for general purpose applications, fine thread applications tend to have many benefits that make them the ideal choice when specifics matter. Fine threading has a higher tensile strength than coarse threading and it can be measured more accurately. Making them the ideal choice for specific strength applications.

Fine threading consists of very shallow peaks and valleys when compared to coarse. As a result, tapping a hole for fine threading can be significantly easier as there is much less material to cut to form the threads. Fine threading also has a very shallow pitch (helical angle). This makes vibrations less effective at loosening fasteners over time. Fine thread fasteners are ideal for environments where vibration is considered an issue.

Now that you know how to compare coarse thread vs. fine thread fasteners, you can make the right choice when deciding on which fasteners you need for a project. For more information about fasteners, check out our Fasteners 101 reference pages.

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.

Helpful Resources

10 Quick Tips and Tricks for Using Fasteners

As a fastener business we often get some hard questions about fasteners. Sometimes though, we get questions that seem obvious to us because we have been in the industry for so long. Its hard to tell when something is common knowledge or simply something we know because we work in the industry. To remedy this, we sat down and decided to make 10 quick tips for using fasteners that outline some of the basics of fasteners we think everyone should know.

1. Don’t Use 18-8 Stainless Steel In or Near A Salt Water Environment

Salt water is great at causing rust and reducing the life of fasteners. To remedy this, we recommend using stainless steel but the correct grade of stainless steel needs to be used. We recommend using only a 316 grade stainless steel within twenty miles of the salt water environment. Otherwise the risk of oxidization (rust), even in other grades of stainless steel, are greatly increased.

2. Always Mate Hot Dip Galvanized Fasteners With Other Hot Dip Galvanized Fasteners

Hot Dip Galvanized fasteners are coated in a thick zinc protective, called hot dip galvanization, to make them less susceptible to oxidization. This thick coating creates a layer on the threading that will not match other materials that do not have this coating. Fasteners that get hot dip galvanized and have different spacing in preparation for this change in thickness. As such, they should only be used together to avoid any compatibility issues. Pro Tip: When installing fasteners it is recommended that you always try to use the same grade and material. Mixing can lead to uneven or poor results depending on the materials.

3. Always Use Fastener Lubricant on Stainless Steel Fasteners

Stainless Steel Fasteners have an invisible coating on them which makes them less likely to oxidize. The trade-off is that this coating can also cause friction between the fasteners (nut and bolt) during the installation. As this heating up occurs, the threads jam and can actually weld to each other. This is a process known as galling or cold welding. To mitigate such risks, simply apply a small amount of fastener lubricant, such as MRO 2400 Marine Grade Anti-seize, to the fasteners before installation. Not only will it deter galling but it can also help to extend the life of your fastener.

4. Always Use The Right Size Screwdriver

A Phillips head is a Phillips head, right? Wrong. Phillips head screwdrivers can also come in different sizes. These sizes may not seem to make a huge difference to you, but to the fastener the difference between a properly seated drive and one that is loose could mean a stripped head. Always make sure the driver sits fully seated into the drive recess, if there is play room between the drive and the recess, you need to find the appropriate sized drive or risk of stripping is greatly increased.

5. Never Use Stainless Steel and Aluminum Together

Stainless Steel and Aluminum are metals that have very specific cases where they can be used together. If they are used together improperly, there will be a transfer of electrons between them which can compromise the integrity of the materials leading to what is called galvanic corrosion. The easiest way to avoid galvanic corrosion is simply to use materials that match.

6. Always Pre-Drill Hardwood Before Installing Screws

There are times with softer wood where you can get away with not pre-drilling holes (although we do not recommend it). You should ALWAYS pre-drill hardwood. Hardwood is much more likely to crack or split when a screw is installed. This can ruin the finish of many products and weaken the integrity of others. Always, always, always pre-drill to ensure you do not ruin your work.

7. Stainless Steel Is A Soft Metal

This is a question we get constantly. Stainless steel is considered to be a soft metal. There are versions that can become hard metals by heating them up to change stainless steel’s properties. This process is normally called heat treatment.

8. Do Not Mix Fine and Coarse Thread Fasteners

Both fine and coarse thread fasteners have different benefits and should be used accordingly. However, it often seems that people attempt to mix them whether its by not knowing they are different or not understanding the measurements. You cannot mix threading. It will ultimately ruin the threading and result in damaged and unusable threads or a jammed fastener assembly. We recommend utilizing our Fasteners 101 section before purchasing to ensure our customers have a solid grasp on the concepts to help them purchase the fasteners they need.

9. Don’t Over-Tighten Fasteners

Fasteners have a max recommended torque for installations. To achieve this we recommend a torque wrench when installing fasteners. You can set the wrench torque so that it will slip after that force is reached. Over-tightening fasteners can actually damage the threads and compromise the integrity of the bolt.

10. You’re Not Invincible, Wear Safety Gear

We constantly and consistently see people work with fasteners without using the appropriate safety gear. This is our most important tip for you. No one is invincible. Many of the injuries can be avoided by simply wearing the appropriate gear. You will find the safety glasses much less annoying when it is preventing metal shavings from flying into your eyes. This gear exists to protect us from harm so we can build truly amazing things. Use it to keep yourself building.

There you go those are our top 10 quick tips and tricks for using fasteners. If you need more information or have questions we did not answer. Please do not hesitate to call at 866-573-0445.

Top 10 Quick Tips & Tricks For Using Fasteners

Top 10 Tips & Tricks Transcript

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Bob: Welcome back to Albany County Fasteners – Fasteners 101. I’m Bob and today I wanted to give you the do’s and don’ts of fasteners. So let’s get started.

My first tip is never use 18-8 stainless steel in a coastal environment where you have salt water. You must be (at least) 20 miles away to use standard 18-8 stainless. Only use 316 stainless in a coastal environment.

My next tip is: Only use hot dipped galvanized fasteners with other mating hot dip galvanized fasteners. In other words, use a carriage bolt that’s hot dip galvanized with a nut that is hot dip galvanized. Never mix them with other finishes like zinc or plain.

When using a nylon lock nut, always use a fastener lube never use a motor oil, wd-40 or soap. These things will negatively impact the fastener over time.

My number four tip: Use the correct driver for the screw that you’re installing. A lot of people use the wrong drivers.

Never use stainless steel with aluminum. It creates a galvanic reaction between the two metals. You’ll start to see rusting and pitting between the two materials. Always use a neoprene washer between them. So this way you don’t run into that problem.

Always pre-drill hard wood. That’s a must whenever you’re installing a fastener. Specifically a wood screw, a deck screw, a sheet metal screw into wood it’s very important. Otherwise, in hard wood, you risk the situation of cracking or chipping of the wood.

Tip number seven which is really a question “is stainless steel a hard metal or a soft metal”? The answer is: it’s a soft metal. So it’s not always good to use in a structural application.

My tip number eight: Never use coarse fasteners with fine thread fasteners or OEM. Don’t use coarse with OEM or fine with OEM. Typically they will not work together.

Tip number nine: Do not over-tighten fasteners. By over-tightening, you can damage the threads and the integrity of the bolt.

Do you think you’re invincible? Always use protection! Glasses, hand gear, body (gear) depending on what you’re cutting. Always use a guard on the saw. Never remove them.

Top 12 Tools Everyone Should Own

It’s a common question in our industry. “What are the top tools everyone should own?” We sat down with one of our fastener experts (who has years of construction experience) to ask him what his top 10 tools were. Unfortunately, he couldn’t get decide on only ten tools, but he was finally able to decide on his top 12 tools everyone should own.

12. Channel Locks

Our fastener expert chose channel lock pliers as one of his top twelve tools. These pliers are an adjustable set of pliers used for pinching and grabbing. They can be used on many applications are provide one tool to get multiple jobs accomplished.

11. Circular Saw

Circular saws are one of the more versatile saws available. Due to its convenient size and multiple uses, this saw made our fastener expert’s list. Many saws are great at what they do but they are often cumbersome and can only perform one type of cut. Circular saws make our fastener experts list for their portable and versatile functionality.

10. Ratchet Set

Ratchet Set (imperial and metric) – Ratchet sets are excellent tools for quickly installing bolts and nuts. In fact, it beats the wrench for us due to its ease and efficiency. Bob told us that when installing multiple bolts quickly a ratchet set is the way to go. We cheated a little here because Bob told us to make sure we had both an imperial and a metric set.

9. Center Punch

A center punch creates an indent in a material by using a sharp point and “punching” it. Too often you will try to drill into metal and find that the bit will not have anything to center on. This can cause frustration for the user and damage the material’s finish. To counteract this, using a punch will give the bit something to center on which reduces the chance of it walking during the drilling process.

8. Drill Bit Set

Bob recommends a size range of drill bits. A drill bit set, rated for the material you run into most, with secondary options for other materials is a good choice (although its likely you will need a wood and a metal set). Without drill bits, there would be no holes for your screws and bolts to secure materials together and build something amazing. As a tip, Bob also recommends cleaning off your bits after use and properly storing them to extend their life.

7. Cordless Drill

A cordless drill is a must have these days. Before installing most screws, a hole should be drilled. Before installing bolts, a hole needs to be drilled. Once, your hole is drilled, the screw needs to be driven. Most cordless drills also offer attachments for driver bits. This means you can drill and drive all from one tool for maximum efficiency.

6. Level

What good is hanging a new picture or putting up a new shelf if they look bad? A level is the tool used to make sure what you have, or install is perfectly well, level. Picture frames will look out-of-place if they are not level. A pool table will skew the results of a shot. You may even find things falling off your shelves! Whatever project you’re working on, make sure its level WITH your level.

5. Hammer

The Hammer, a brute tool that can take a surprising amount of accuracy and care to use (unless you enjoy smacking you fingers). A hammer with claw is probably the most common type of hammer and it is used to both drive and remove nails.

4. Tape Measure

This one is simple; the tape measure is used in all measuring applications. From determining the size of a room, to finding screw length. A tape measure is a must have for anyone in the professional industry or the DIY-er who wants to get into their own projects.

3. Screwdrivers (Phillips and Slotted)

Again, we know we are cheating a little here but when it comes to screwdrivers, you’d better have both. Screwdrivers are used virtually everywhere from furniture to your car. In fact, you would be hard pressed to find a device that doesn’t have at least one screw in it. Although Torx and square drive screws are becoming more popular, the overwhelming number of devices today have either a Phillips or a slotted drive. While we recommend having each kind, you can get away with a quality set like this: Vega 53 piece insert bit and driver set.

2. Vice Grips

Our fastener expert’s number two tool was his pair of vice-grips. Vice grips are a tool that can be utilized in many applications as well. They work by adjusting the clasping claws on the head of the grips. Once adjusted, attach to the fastener in question and squeeze. The device will lock in place creating a secure hold on the fastener. This allows for a much better grip than many tools will offer if the primary gripping point is damaged. For example, when a bolt begins to strip, a pair of vice grips can be sized and get a better grip on the bolt than a wrench making it removable (just make sure to get a new bolt!).

1. Step Stool

Bob’s top tool was a stepladder which took everyone by surprise. Step Stools are essentially just short ladders. Bob explained to us how often he would be doing an installation and needed to reach as far as he could to attempt to drill or place a screw above his head. Utilizing a step stool will not only make the job significantly less tiring by removing much of the strain on your shoulders, it also allows you to place the proper pressure on a drill/driver to ensure for proper installation.

Now that you know the Top 12 Tools everyone should own, it’s time to go start working on your own projects!

Top 12 Best Tools Everyone Needs On The Job

Top 12 Tools Transcript

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Bob: So I had my top 12 list of tools here and I just want to go over and show you what I have, that I’m constantly using anytime I’m doing my projects.

25 Foot tape measure – Must have.

My number one tool though is this step stool. Used in many applications you got to have that.

Vise-grips – Must-have in your tool chest.

Adjustable wrench – great for plumbing projects.

Must have. A hammer. Probably 90% of the projects that you’ll do around your house, you’re gonna need a hammer.

Screwdrivers – flathead and a Phillips head – those are two most important.

I have a ratchet set – good to have a ratchet set that fits Imperial and metric.

A punch – This is self engaging punch. Spring activated, must-have tool and to go with that, a full set of drill bits for metal or for wood.

Cordless drill. Used in 90% of the projects that I do.

Level – Gotta have a level. Most important tool around. You always have to install things that need a level: pictures, bookcases, desks. Always need a level.

And of course my last one which is my circular saw. Used all the time.

Thanks for watching!

What Does Anti-Seize Do?

Why Should You Lubricate Your Fasteners?

Fasteners are amazing holding tools used to secure materials together. They do (just like anything else) have limitations that can affect their performance. This is why you should lubricate fasteners.

The Installation Process

Fasteners in certain materials, a good example being stainless steel, have an oxide or coating covering the fastener. When you begin tightening the nut to a bolt, pressure builds along the threads. If not seated properly, tightened too quickly or even if the threads are just not perfect, there is a chance that this added pressure will shear the threads and cause imperfections. The result is that both the bolt and nut will be stuck together. In extreme cases, the metals can actually fuse together which is know as cold welding. Both of these symptoms fall under the category of thread galling.

The (MRO) Solution

Anti Seize used to Lubricate Fasteners

So now we know what can happen if we don’t lubricate fasteners but what do we do now? Find a great lubricant! MRO Anti-seize solutions offer a great way to limit these effects. Anti-seize is simply a specially designed lubricant that minimizes friction on fasteners which in turn will help prevent the building pressure from shearing the threads. It can also make normal installations of any material much smoother. Anti-seize solutions can also provide a very light coating of protection until it has worn off. This can help maximize the life of your fasteners.

Coarse Thread Vs. Fine Thread Fasteners

Which One Should I Use?

Coarse Thread

Fine Thread

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

10 Quick Tips and Tricks for Using Fasteners

1. Don’t Use 18-8 Stainless Steel In or Near A Salt Water Environment

2. Always Mate Hot Dip Galvanized Fasteners With Other Hot Dip Galvanized Fasteners

3. Always Use Fastener Lubricant on Stainless Steel Fasteners

4. Always Use The Right Size Screwdriver

5. Never Use Stainless Steel and Aluminum Together

6. Always Pre-Drill Hardwood Before Installing Screws

7. Stainless Steel Is A Soft Metal

8. Do Not Mix Fine and Coarse Thread Fasteners

9. Don’t Over-Tighten Fasteners

10. You’re Not Invincible, Wear Safety Gear

Top 10 Quick Tips & Tricks For Using Fasteners

Top 10 Tips & Tricks Transcript

Top 12 Tools Everyone Should Own

12. Channel Locks

11. Circular Saw

10. Ratchet Set

9. Center Punch

8. Drill Bit Set

7. Cordless Drill

6. Level

5. Hammer

4. Tape Measure

3. Screwdrivers (Phillips and Slotted)

2. Vice Grips

1. Step Stool

Top 12 Best Tools Everyone Needs On The Job

Top 12 Tools Transcript

What Does Anti-Seize Do?

Why Should You Lubricate Your Fasteners?

The Installation Process

The (MRO) Solution