Screws vs Nails – What’s the Difference?

Screws vs Nails

It’s one of the more common questions asked in our industry. Which applications should use screws and which should use nails? While there is no easy answer as we will soon learn, The basic theory is simple. Screws for holding power and nails for shear strength. But just what does that mean? How do we know when that kind of force will be present? To answer these questions, we sat down with our fastener expert to discuss screws vs nails.

The Basic Theory

Screws

Screws are fasteners with a drive located in the head and threading that protrudes down the length of the shank. Screws (most of the time) require a pre-drilled hole and can often cut their own threads into materials they are rated for. For the sake of argument, we are going to be discussing a deck screw for this example. Deck screws are exceptionally engineered to hold two boards of wood together tightly and efficiently.

Nails

Nails are fasteners with a flat head, smooth shank and sharp point. Nails are driven by a hammer into materials to hold them together. They can be installed faster and are cheaper than screws. In this case (and to explain the theory), we will be using a smooth shank screw as our example.

Comparison

So when comparing nails vs screws we need to consider a few factors. Grip strength and shear strength being the two most important. To view these forces we’ve created some simple diagram. Assume that the arrows are the forces acting upon the two boards in the pictures shown.

Grip strength, in this instance, will refer to a fasteners ability to hold in wood. When a screw is driven its threads dig into the material around it. This makes screws more difficult to remove as they need to be spun out of the wood. So as an example, lets take a tray with a wood board screwed onto the bottom. This board is going to be able to hold quite a bit of weight without the screws falling out. Conversely, if nails were used they would not be able to hold the same amount of weight without starting to loosen.

Shear Pressure — Force being applied on the sides of the two boards.

Now lets look at shear strength. Shear strength is the amount of force a fastener can handle from the sides. A nail, has more elasticity than a screw. This means as forces are pushed against the sides of a nail, the nail can bend slightly to accommodate these pressures. A screw conversely has very little shear strength. Screws that are bent will almost always snap when trying to be straightened.

So which is better a screw or a nail?

The answer is: It Depends. In many applications where force is placed vertically along the installation, a screw is a better choice, but in situations where the force is placed adjacent to the installation a nail is a better choice.

Now a real life scenario where we see this happen all the time is in decking. The forces wind creates on the bottom of a deck (especially in hurricanes) can be catastrophic. As a result, when you install hurricane ties, you want to use nails to install them as the forces that act upon them will shear screws straight off. But these same forces that come up from underneath a deck will push on the bottom of the boards you walk across and since that pressure is pushing directly against the fasteners head, you will want better grip strength making screws the appropriate choice.

As with all fasteners, each has its own unique positive and negatives and must be chosen accordingly. There are also outliers to this rule. Ring shank nails are one of the many varieties of nail available that can provide better retention add some very strong adhesive to that and it’s even less likely to come out. In theory though, the answer is simple. Need grip strength? Use a screw. Need shear strength? Use a nail.

Correct pressure to use a screw for The correct pressure to use a nail for

What is Torque Control?

Torque Control and Related Terms

Torque is the force applied to something to make it spin (rotate) in machinery. Torque in relation to fasteners is the resistance faced when installing a fastener. Torque control then is simply controlling the amount of torque placed on a fastener without damaging it by over-tightening.

Prevailing Torque	Measure of a screw or nuts frictional resistance to rotation.
Prevailing “Off” Torque	Highest back-off torque on a torque wrench on the first rotation of a screw or nut upon removal.
Installation Torque	The initial torque amount used to install a fastener before Pre-load.
Breakaway Torque	The minimum torque required to start rotation into a nut (in the case of a bolt) or into a pre-tapped hole (in case of a screw).
Breakloose Torque	Minimal torque required to begin the disassembly of a fastener assembly.
Seating Torque	The torque required to produce pressure onto the installation material causing compression by the fastener.

Torque Wrenches are one of the easiest ways to ensure proper torque is met. Simply set the wrench’s torque and then when the maximum is reached the clutch will slip. This slip means the wrench stops putting any more torque on the fastener and it has reached its optimal torque.

Fastener Mechanical Properties

What Are Fastener Mechanical Properties?

Fasteners are arguably the most commonly used connecting items. You can find them anywhere you look. They hold your house, toys, car and just about everything else together.

When dealing with the many kinds of fasteners available, it is critical to deal with all of the components of fasteners. But just what is tensile strength? What about shear load? Join us as we dive deep into understanding fastener properties and discover what these industry terms mean.

Tensile Strength	Refers to the maximum load under tension a fastener can handle before being compromised.
Tensile Load	Refers to the maximum load (pressure in tension) exterted by the installation material against the fastener before it will compromise.
Ultimate Tensile Stress	Refers to the estimated minimum where a fastener will compromise its integrity.
Elongation	Refers to the stretching and deformation that will occur to a fastener caused by a load exceeding its capacity.
ProofLoad	A test load a fastener MUST be able to hold without causing any compromise in its integrity. Considered the maximum safe load of a fastener.
Pre-Load	One of the most important measures in the industry. Refers to the axial load placed on a fastener. Pre-load is considered to be 75% if the proofload.
Shear Load	The load a fastener can handle when two materials are pushing against each other onto the fastener. This will vary if the load is pressing against a fasteners shoulder versus it’s threading.
Torsional Strength	Maximum torque a fastener can handle before the threading becomes warped or destroyed.
Yield Strength	Refers to the load a fastener can handle before begining to stretch.
Yield Point	The definitive point a fastener can no longer handle the load before stretching.
Fatigue Strength	Fasteners expand and contract many times due to elemental stresses. Fatigue strength is the maximum number of times this can occur in a cycle before some critical component of the fastener becomes compromised.
Creep Strength	Refers to a fastener that has heated up and elongated due to the load under pressure and the heat.
Hardness	Refers to a fasteners ability to scratch, mar or otherwise damage another material without itself being damaged.

Now that you know what these terms mean, you can begin using them to help you find the appropriate fasteners for your job.

*Not all fasteners are made equal. Always follow the specifications from where you buy your fasteners to get the best results.

How To Drill A Countersunk Spade Bit Pilot Hole

Drilling a Countersunk Pilot Hole In

Wood

Today we are going to learn how to make a countersunk pilot hole in wood from our fastener expert, Bob. He told us that he has seen many people attempt to drill this hole and approach it the wrong way. Most people start the same way the would if they were using a standard drill bit. First the pilot hole, then the countersink. This however, does not work with spade bits due to the way the drill bit is engineered.

A countersunk hole is where a secondary larger hole is cut on top of the first hole so that the head of the nut or bolt can sit inside of the material and not be exposed. There are many applications for these types of holes and you probably see them around quite often without even realizing it. Fasteners may be countersunk in furniture, buildings, banisters, decks, etc.

Spade Bits have a triangular tip that digs into the wood before the outer edges of the bit do. This not only acts as a guide for the rest of the bit but as a stabilizing factor as well. Bob told us that if we drill the pilot hole first we would have a hard time drilling the countersunk area and would damage the wood.

He set out to give us an example by showing us the proper way to install a lag screw into some wood.

Tools

5/16″ Spade Bit (For the pilot hole)
1-1/4″ Spade Bit (For the countersink)
9/16″ Socket
Ratchet
3/8″ Lag Screw
Safety Gloves
Safety Glasses

Drilling

The first step when drilling a countersunk hole with a spade bit was to start with the countersink itself. This will allow both the larger spade bit (countersink) and the smaller (pilot hole) to grip the material and prevent “wobbling”.

So first we drilled the countersunk hole and then we set about drilling the pilot hole inside of the countersunk hole. It was a surprisingly easy task.

We tested this again by doing the process backwards and determined that what our fastener expert had said was true. Not only was it difficult to drill the holes but there was some significant chipping to the surface of the wood. While we were able to drill the hole the result was an unprofessional mess.

Our fastener expert also chose a very large spade bit for the countersink which he later explained was to allow breathing room for the socket that he would use to install the lag screw. Otherwise, it will be difficult to install without the socket getting caught up in the hole.

The Result

using blue tape to prevent chipping in wood during drilling

After comparing the two holes, we determined that the hole we drilled first (properly) was much better. The edges were smoother, barely any chipping on the outside of the wood, everything was in good shape. The second hole was abysmal. With chewed up and chipped edges from the bit bouncing around. Our fastener expert said we can do even better. Pulling out a roll of his trusty blue painters tape, he laid it over the wood and drilled the countersunk pilot hole again. This time there were virtually no chips in the wood at all. The tape re-enforced the edges of the hole being drilled to prevent chipping.

Below are the three drilled holes and the results:

Hole 1 – Left – Was done properly with no tape. Light chipping occurred around the edges but was still a fairly clean.
Hole 2 – Middle – This hole had the pilot hole driven first and as a result has heavy chipping around the external edges. The inside edges also weren’t smooth from so much bouncing around.
Hole 3 – Right – Done by first covering with blue tape, then drilling the countersunk hole and then the pilot hole, this hole is the cleanest of all three with virtually no chipping and clean sides.

How To Drill a Countersunk Pilot Hole With Spade Bits

How To Drill a Countersunk Pilot Hole With Spade Bits Transcript

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Bob: Welcome back to Albany County Fasteners – Fasteners 101. I’m Bob and today I’m going to show you how to properly drill a pilot hole, along with a countersink, using a spade bit. So let’s get started.

I have here two Spade bits. I’m going to drill a pilot hole and a countersink with these two Spade bits. These are wood Spade bits and I’m going to drill for this 3/8″ lag screw I have here. I have my ratchet too.

So, what’s key here about the pilot hole, I’m sorry, about the countersink hole is that you need to have enough diameter to be able to use a ratchet to drive the lag screw. It’s important that you get the right size. So for a 3/8” lag screw, I’m using a 5/16” pilot hole and a 9/16” socket. I’m using an 1-1/4” spade bit to basically give me enough room. So if this moves around, it’s not tight. It makes it very hard to get the socket out. It becomes a real issue.

Now I’m going to use a ratchet to put this in. There’re many other things you can use, such as a pneumatic. They have some cordless drills that you can use today to install the lag screw. This is for demonstration purposes, so I’m just going to do this.

The first thing that you need to do, and what not to do, is you never drill your pilot hole first. If you drill your pilot hole first, which I’m going to demonstrate to you what happens, if you drill your pilot hole first. So using your 5/16” for the 3/8” bolt, when you go to drill your countersink, it’s gonna swash around inside and undo your pilot hole. It won’t guide properly. With a spade bit, this little diamond shaped blade point is what guides the drill bit and holds it in place. If you were to drill this hole with the Spade bit for 5/16”, it’s just gonna be too big. Then this is gonna jump around, and it’s going to jam the drill and you possibly could hurt yourself. So I’m gonna demonstrate this now. I installed my spade bit into the drill, and I’m basically ready to do my countersunk hole. You always have to do your countersunk hole first for the head, and then again for how far you’re gonna go down. Basically, I’m gonna countersink approximately 3/4” to 1” into this wood. Now I have gone down about 3/4”, which will be a nice countersink.

I’m gonna switch out my bit and put my pilot hole in, tighten that up, and put this bit in. I’ll continue drilling until I get through the other side. Always back up to bring the wood shavings out. Well that didn’t work right. Huh. I guess I didn’t tighten it enough. I’ll just tighten it up. I’m gonna take my ratchet and drive it in. There you go. That’s done.

Now I’m gonna demonstrate for you what happens if I drill my pilot hole first. Now this is not a big pilot hole but if you were using a larger size, such as 1/2”, it’s gonna be more severe. I’m gonna drill the pilot hole first. You can see this nicely drills through. No problem. Switch out my bit to do my countersink. As you can see here, this will now wobble around. With that wobbling around, you’re not gonna get a totally centered countersink. It’s gonna want to take off. I have to be cautious. If I go too fast it’s gonna jump around on me and it may wedge the bit in the hole and start to twist at my arm.

You can see already how this is chewing away at the wood. That’s not what we’re looking for. You see how that’s jumping around? You can do it, you can get the countersink done, but it’s not precise. It’s not clean. It doesn’t give you a nice clean finish. So at the end of the day, you really want to drill your countersunk first and then your pilot hole.

Another thing to do, if you wanted to stop the splintering, is to put some blue tape over the area you’re gonna drill. This is very good for marking as well. You can write on blue tape. Let me just find the beginning of this tape…there it is. This will stop splintering from happening when you’re using a spade bit. So I’m going to do another countersink. That gives you a nice clean surface. You can see how nice and smooth that cut is.

I’ve used these bits before. I’m doing this for demonstration. These bits are not brand-new bits. (With) Brand-new bits you would have a nice, sharper point. I think you can see how nice I could drill through here. Then you take off the tape and there you go.

That’s how you properly drill a countersunk with your pilot hole. Thanks for watching.

How To Use An Auger Drill Bit

Drill Bits for Wood

Auger drill bits are bits used to drill holes into wood. They are commonly used for boring holes into bulkheads and general timber applications. These drill bits come with a spiral drill bit head which, when drilling, is designed to pull the bit into the wood so you do not have to apply excessive pressure.

Lets Begin

Today we wanted to show you how an auger drill bit works. Most of these drill bits have a long stem on the end which attaches to the drill chuck. Then the

Begin Drilling tip of the bit can start “biting” into the wood and pulling the rest of the bit into it. Before beginning your drilling application, you may want to put a piece of painters tape over the hole you plan on drilling into. Auger bits may chip the wood they are drilling into resulting in an unclean look. Painters tape should deter this from happening.

Auger bits are also designed to be run very slowly and with minimal pressure. Remember, the tip of an auger bit will help to pull it into the wood so you don’t need to apply a massive amount of pressure. We recommend about 600 rpm when drilling.

What About Nails?

Auger bits are incredibly durable and Drilling through a deck screw have the strength and cutting power to drill through nails and screws. It is important to maintain a slow speed and let the bit do the work. Once through the nail just continue on and finish the hole you are drilling.

What are the advantages of using an auger bit?

Auger bits have the capability
Drilling deep.
Drilling neat uniform holes.
Prevent the clogging of boreholes
Auger bits allow for efficient clearing of wood shavings as a result of their wide and deep flighting.

How To Use Wood Ship Auger Drill Bits

How To User Auger Drill Bits Transcript

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Bob: Welcome back to Albany County Fasteners – Fasteners 101. I’m Bob and today I’m going to demonstrate the use of an auger bit.

So I have here an auger bit. This is a 5/8″ auger bit. 8 inches long overall. The stem part here which is pretty typical on all ship auger bits (which is what they’re really called here – Ship auger bits).

This part here is about 3 inches and its typical through all sizes. The lengths these come in anywhere from 8 inches to 18 inches long. I think there’s a 12 inch, maybe there’s a 10 inch, but you know you’ll have to decide based upon what you’re doing.

Also, auger bits they have this little screw in the front here. It is to pull the auger bit forward as it drills. These auger bits also will break or cut nails as they go through.

These are very cool bits. Used on ships and many other different applications but I’m going to demonstrate this now on drilling this auger bit into my sample piece of wood here. This is only for demonstration. Also, you should know that you should not run and auger bits more than 600 rpm.

So, slow as you go. It just draws itself right in.

Now it did splinter in the front here a little bit. If you don’t want it to splinter like this you take a piece of tape, blue tape or painters tape, and you put that on the front before you drill and that’ll prevent this from splintering the front face of the wood.

So I want to demonstrate to you an auger bit going through-they say that they can go right through nails, which I know they can, but I have a deck screw here that’s right in the top going down and I want to demonstrate to you an auger bit cutting its way through a deck screw. This would be a stainless steel screw. Let’s give it a shot and see what happens.

I’m up against it right now. Right through. Coming through the other side. Look at that.

So there was some resistance there but it cut through the deck screw. I think that was a number 10 deck screw, number 10 wire. So that would be equal to a like a Ten penny nail or a duplex nail. No problem. Right through with that baby.

Thanks for watching.