Go watch Project Farm's video on screws & nails. This video is how to do a bad test, and build something wrong. If all the weight is on ANY screw or nail it's dangerous. Fasteners hold lumber and brackets. Lumber holds the weight.
I don't think this video was about what is the right way to build something, in fact the other video he references shows the right way to build a shelf for example. In this he was only testing what would happen to the screws. He wouldn't be able to do this test if he built a proper shelf because the blocking would take the weight and stress.
@@procrastinatingnerd but that isn't how screws work. The screw is not strong against shear forces, because it is not designed for that. The screw in this case is supposed to pull the vertical and the horizontal pieces of wood together, and the friction between the two surfaces caused by the screw pulling those two surfaces together should hold it up. He isn't testing what would happen to the screws or how good those screws are. He is testing what happens to those screws if you are using them wrong enough (which he does).
@@edededededededededede He wasn't just testing the screws shear breaking force, this simple test showed the differences between the screws in a simple way. He was also testing the thread holding strength which DOES make a difference in how tightly the screws can hold the surfaces of the wood together and maintain that friction. I get some of what your saying, this wasn't a real world test for the screws, but by your logic, it truly wouldn't matter what screw is used because if the thing being built is built right then any of these screws would work. But this wasn't to test just that. He actually had a few different tests in this video. For example he confirmed for everyone that Philips head screws are a terrible choice for this application. That has nothing to do with the screw strength. Using the screws wrong enough will tell you a lot about them!
There are screws that are made to take weight, they are called structural construction screws. Look on the box, it will tell you if they are for structural or non-structural usage. You should know with how you are building and assembling a project if you are making the screw support any weight. If the fastener does take weight make sure the box specifies structural usage.
Came here to say the same thing about watching Todds (Project Farm) videos. Todd is very scientific about his approach so that he doesn't influence anything. (Also, regarding proper way to built something, or whether or not the screws are meant for this type of force is somewhat irrelevant. It's true, however, this is more of a what if they did receive that type of force? It's a great video idea for most people building some quick shelving in their garage, house, etc.)
Big problem with your testing, you kept reusing the same hole in the vertical board, the very first screw distorted the hole and made every screw after that to bend down and easily pull out of the wood. In other words, you should have used a new hole each time. See angle of screws on uprights at 3:28
also stomping is not a very even application of force nor the same amount each time, and then consider the differing weakness of wood given the screw location. I would have been happy with the general test itself if he didn't give an actual conclusion
The testing is also aimed at shock/shear strength. Lumber fasteners seldom fail in that manner. You should be testing the fasteners ability to deform (bend) without failing. Imagine an old barn that just wants to lean over.
From a physics perspective, there is an incredible difference between static load and kinetic force. A more reasonable test is you adding weight gently until the joint fails. The torque of the stomping is essentially thousands of lbs vs the real weight it can hold with is a 1000 lbs.
I agree with you in general, but sometimes if you're placing something very heavy -- like a crate full of tile or some cement blocks or a benchtop drill press -- onto shelving, you might lose your grip and accidentally drop your load onto the shelf from a few inches above the shelf. So sometimes shelving and decking have to withstand dynamic loads not just static loads.
Torx head screws cured my PTSD and allowed me to fire my psychiatrist. 😃 I'm old enough to remember the transition between straight/slotted drive screws to Phillips, Phillips to Roberts, and more recently, Torx. Each one was an improvement over the preceding drive type, but Torx is by far the least frustrating. I recall working on crews and hearing that all-too-familiar sound of a Phillips bit losing it's bite and stripping out the head of the screw. Finding a decent quality Phillips driver bits was always something I was bent on improving, and even with good quality bits, one HAD to provide PLENTY of force into the screw to keep the bit engaged AND have them aligned almost perfectly. Now that Torx is on the scene, yeah they're more expensive, but they're also saving time and frustration, and that is not so easy to put a dollar value on.
I'm old enough too. I think that we forget that Phillips screws were designed when power tools were not even a twinkle in someones eye. Sure they cam out quickly when you put power to them, not so much when you use a screw driver. They are just old technology that we don't seem to be able to move on from. Me, I'm a Roberts fan all the way (thank Kreg tools for setting me on that path) but I'm quickly coming around to Torx, specifically GRK. Love that wide washer head on the larger ones.
I don't know how many times that I have stabbed myself with a Flathead or a Philips screwdriver and it hurts, Torx screvdrivers minimize this unless the bitsize is small enough but then I am working with electronics and not woodworking so the risk is already minimized because most often the forces is less. but sure I have stabbed myself doing electronics when the screws are really stuck too 😅 at that scale it dosn't matter what kind of bit you use, them all will penetrate your skin
Phillips screws are DESIGNED to cam out. If you ever install drywall/sheetrock you will see how this works. I am pretty sure they were designed that was for use on aircraft so they would not be over tightened. (check this as I have not researched it so it's just a rumor)
Okay, playing chords when you showed Dmaj and Dmin was pretty clever. Also, I know that this wasn't meant to be one, but for a scientifically accurate test, you'd need to make some changes to the set up. 1. Use a machine to apply the load. This can be a jack, a screw, or something else. It just needs to be able to apply a consistent load to the test article. 2. Use something to measure the force applied. It should have a way for you to measure and record the peak force, since that'll be force at which you suffered a failure. 3. Try to keep from changing more than one variable at a time. There's a few things to consider here. The pilot hole, the shank diameter, the cut (geometry) of the screw thread, the major and minor diameters of the thread, the pitch of the thread, the material of the screw, the number of screws, the spacing of the screws, and the composition of the boards used to make the structure. All of these are going to affect the performance of the screws. As some have pointed out, the hole that you put the screws into was the same hole, and it was changing with each test. 4. There's a difference between shock loads, dynamic loads, and static loads. Jumping on the test rig generates a shock load. This applies a lot more force to the structure for a given mass. Force is mass times acceleration, and you're going from several meters a second to 0 in a very short amount of time. Dynamic loads change over time. This is what you have when you gradually increase the force applied until something fails. This is a good way to test when you've hit the physical limits of a connection and figuring out how much something can hold given a specific safety margin or factor. (If you want a 2 times safety factor, you'd take the force that the structure failed at and divide by 2.) Static loads don't change over time, but the thing is, everything is plastic given a fine enough resolution (i.e. accuracy of measurement) and enough time (on the scale of millions of years, stone and rock are very much plastic.) Applying a static load over time can tell us how the connection will perform over time. Sure, it might be able to resist a given force that's slightly less than the force needed to cause a failure, but you're stressing the wood and the screws a lot. Over time, that stress can lead to a failure as it causes the wood and the screws to deform. This is why something might hold for a while then fail suddenly even if the force being applied hasn't changed at all. Something deformed enough to change how the force is being applied and transmitted through the structure. Incidentally, this is also another thing that is affecting your tests. When you jump on it, you're not going up to the same height above the shelf every time. It's always going to be a bit different. Similarly, you're also not landing in the same place each time, which is going to affect the amount of force you're actually applying to the screws. The further from the connection you land, the more leverage you have and thus the more force you're applying to that connection. So, if you want to really see which is better for a given application, you'd need to change the setup to control as many variables as possible. Some things, like the structure of the boards (i.e. the wood grain, moisture content, microcracks and splits, etc.) are going to be almost impossible to control for, but you can still get a pretty good idea of how the screws perform by doing multiple tests and using statistical analysis to get an idea of how well the screws are doing even if there are things you can't control affecting your results. The downside of this, is that it's going to take a lot of boards to do this right since each test will need to be done with with new boards that are part of the connection you are testing at the very least. Don't forget that you also have to worry about the boards transmitting the forces and loads to the connection. As you stress them, they can also change enough to affect the results of your testing.
Screws are strong in the dimension along their length, not in shear. But if the material is strong enough, the clamping force of the screw creates enough friction to take care of the shear force. So with the right material and screw placement, screws can absolutely be all you need.
Drywall screws have a bugle head, designed to gently compress drywall paper without tearing. Used in wood or sheet goods they work like a wedge and split them open easily. And in drywall screws, cam-out is a feature that every screw gun makes use of to help set the proper depth.
2:08 remember the days when finish carpenters drilled pilot holes? Believe it or not, if done right, pilot holes can add strength. You’re removing the internal tension in wood imposed by just driving them straight in. 5:50 difference between #8 & #9 # 10 is approximately 8% between
@@ScottFidler I don't think it requires finish-level carpentry details, but if you're going to put heavy stuff on the shelves and you're bothering to allocate the time to building them, you might as well overbuild them so you never have any issues. For me, spending an extra 30 minutes of time on construction is never an issue. The issue for me is always taking time out of my day to get my tools together for a job, run to the hardware store to buy screws + other materials (and lumber), etc. So if it takes me an extra 30 seconds per hole to drill a pilot hole and I spend an extra 10 minutes building something, the added time is negligible. Similarly, for me, spending 20 cents per screw vs 9 cents per screw doesn't matter at all. It matters for some people, but I can afford a premium screw, and I'd rather pay for a nicer screw that uses torx drive, pulls my wood together well, etc. What wasn't discussed in this video is that I am fully convinced that spending extra time at the lumber yard or hardware store to pick out the best pieces of lumber in the pile can have a huge impact on the strength and stability of your project. I'm not talking about using white oak or some kind of expensive wood. I'm talking about simply picking out 2x4s from the pile that don't have large knots, aren't already splitting, are straight, and have relatively tight growth rings/grain.
@@clutteredchicagogarage2720 A lot of my shop infrastructure is built using furring strips. You can bet I pre-drill/countersink all the holes in anything one-by I use. Two-by I usually only do that at the ends, they don't usually split in the middle.
My house was built in 1996 with a cheap construction-grade wooden attic ladder in the garage ceiling. In 2001 I had a contractor replace the ladder with a higher grade wooden stair unit. I did not pay attention to what he was using to secure the ladder's box frame to the ceiling joists (turns out it was drywall screws!). Forward to 2016, I hired a company to replace my A/C unit in the attic which meant there was sometime two guy plus the weight of the equipment going up and down that ladder. I did not think anything of it as I had been running up and down that ladder for 15 years. As soon as the workers hauled the last piece of the new A/C unit up into the attic, I decided I would climb up there a few minutes later to see how it was going. I got about half way up the stairs when "crash!" - the whole attic stair frame (with stairs attached) fell out of the ceiling!!! Tore me up somewhat and messed up my back, but a miracle it did not kill me! One step higher and that would have done it. After investigating what happened, it was found that the frame had been fastened to the joists with those black/brittle drywall screws and they just sheared off (threads did not pull out). Worked fine for the first few years luckily, but finally failed catastrophically. Thank God they held long enough for those workers to get that A/C unit up there or I would have had two dead workers and a terminal lawsuit on my hands! Went back with heavy construction screws.
mathias wendall has entered the chat. Drwall screws are great for 90% of what I do. I've never had a screw "fail". But that's just my limited experience. For outdoor stuff I use the 3" Grip Rite #9 Exterior Screws.
Many sources in print and online say that choosing the correct wood screw requires having only smooth shank with no threads in the workpiece "on top" (i.e. closest to the screw's head) so that as it's tightened, it pulls that workpiece against the one in which the threads are embedded. Some drywall screws have threads all the way from the head to the tip and some only have a short unthreaded area. If there are threads in both workpieces, then driving the screw doesn't pull them together but rather moves them both in unison. Isn't that enough reason not to use drywall screws for anything but drywall?
So in the final test you made an error. with the GRK screws you put them vertically, which put each screw into different parts of the grain making the force spread across the wood better. and with the construction and drywall screws, you put them horizontally, making them go into the same grain section causing the wood to fail more easily. Also, one thing you didn't mention is the design of the drywall screw head is not to be countersunk into wood. the curved shape as well as the smoothness is to allow the head to countersink into drywall without tearing the paper, and that is why they hold so well. All in all, a good video, and definitely interesting to see how each screw held up to a test like that.
Its a game of surface area, some screws are meant to be used in softer surfaces, meaning they distribute their weight more with the shape and thread. Obviously material plays a part, but in most cases if your screws are breaking you have a different problem.
You needed new holes for each screw in my opinion because of the enlarged hole in the back of the board where screws had already been pulled down. I think that gave the screw room to move more than a fresh hole would have.
@@pilotdog68 You really don't need engineered plans, just read on the box. It will tell you if they are for structural or non-structural usage. You should know with how you are building and assembling a project if you are making the screw support any weight.
when i started building more things within the last year, I bought drywall screws at first because I liked the flat black look. I broke them just below the head over and over trying to sink them without pre-drilling a relatively wide hole, and also trying to drive them flush or below flush. I started buying deck screws and have had zero issues. It's super easy to bore through anything with those and I've had zero failures. Another option I like is cabinet screws for a clean look if the screws are going to be visible, and I trust them not to break like the drywall screws. Pocket hole screws are also a great pan head alternative and I've been using them more in certain situations after watching your base cabinet videos. Built my first cabinet ever just a few weeks ago and thanks to your videos and clear explanations, it turned out great!
Inappropriate use of screws. When I built shelves in my utility room, I cut 3/4" dados in the upright 2x4s and used 3/4" plywood ripped down to 2' wide for the shelves. I only used screws to mount to the wall and to hold the shelves in the dados. The weight is held by the 2x4 wood uprights. After 30 years they are still solid.
I swapped out drywall screws once I started doing a lot of outdoor work. The coated or stainless screws are still the best bet for preventing rust spots.
Drywall screws are not authorized for support construction per building codes in 50 states. I.e. Joists, load bearing walls, must be construction grade or you can expect to unscrew every drywall screw and replace them or receive no reimbursement from insurance companies and building condemned by every city ordinance inspector. Fasteners (those things attached to load bearing construction) can be any material (plastic, stick-ums, drywall screws). For shelving, since they are non load bearing use joinery or brackets off the load bearing structural supports. Or just do what you want and live with the consequences... that is what I would prefer but since I so lots of construction and research building codes for every damn city i find myself in, the ordinance codes are where you want to start. Remember: Fasteners are not load bearing.
My experience as a carpenter is that there are huge differences between screws, but the price is often not a indication of quality. Buy known brands that have a reputation to preserve, since then the quality is often good throughout the lineup. The largest difference between good and bad screws are the corrosion resistance, and the second thing is the overall strength. Screws need to be just stiff enough, but at the same time be able to bend without snapping. let's say you have a huge snowfall or powerful winds that make some of the screws break. You will have a huge problem over time. Since nails are rarely used anymore and we almost only use screws I buy screws by weight or in large quantities as 1000pcs boxes.
Square head srews are better than the torx head. Even though I have plenty torx screws of many sizes, I am slowing switching over to square head screws. Would like to see a comparison test.
I always use deck screws, Brad. The lack of a smooth shank under the head of drywall screws means the hole in the outer piece needs to be larger than the thread. For drywall, it's not necessary because the drywall just crumbles. Also, in my younger days of woodworking, I snapped many drywall screws while tightening them. Bill
23:38 Am I flocking missing something here because I see two dry wall screws behaving the same as the expensive ones despite the voice over conclusion that says the opposite??
Great Video, Someone may have already said this, but I'll add it anyway! For the shear force case, the diameter of the screw isn't what's important. In a shear force case, you care about the friction force between the two surfaces (Created by the screw pulling them together). That friction force is where the strength comes from. The item will fail when you get slippage and a shear force acts on the screw (Which they are not designed to resist). This also means it's really important to create a high force between the two surfaces (Your pre-load) before the screws are put in to fix them. If you do this test again I would clamp the two surfaces together first, then screw them, I think you'll get much better results. For more info look up "Bolted joint design". Keep up the great work!
Obligatory Canadian comment: I'm so glad you're calling out the awfulness of Philips here, but have you ever gotten a chance to try Robertson (or squarehead as it's sometimes known)? It's a particularly good option, and is the best I've ever used.
I made tons of cool stuff with drywall screws because there was a buttload of them in my garage when we bought our house. I never had a problem and they worked great. I even bought more when I ran low on them. They actually sell some with self-tapping tips of different designs. Then, there were some projects that were basically just toys for the kids that got left outside. They stayed together perfectly fine but when I disassembled them to either fix stuff or use the wood for other projects, they were already trying to rust to death. I never had a failure because there weren't any screws that were critical components but it definitely let me know that this wasn't the proper application for them. However, if I were building something that I knew was staying inside and I only had a box of drywall screws, I wouldn't hesitate to use them. They don't seem to do great being driven in with an impact but a standard drill seems to do fine with them.
1. So this testing wasn’t perfectly engineered. It was VERY informative. Great video! 2. Drywall screws and many others with dubious coatings are dangerous in exterior or otherwise corrosive applications. I used drywall screws to assemble an outdoor shed which was then painted. After a decade exposed to weather, the drywall screws literally disintegrated and disappeared beneath the paint. Same would be true of every other screw with a cheap, thin coating including electroplated zinc. 3. Among reasons for using screws is disassembly. If paint is applied to surfaces, embedded screw heads become difficult to locate and are clogged, making disassembly nearly impossible. Screwed assemblies can’t be pried slightly to locate & expose screws for removal without causing damage. Nails aren’t so bad. They often make prying and non-destructive disassembly possible.
Stumpy Nubs has a similar comparison. TL;DR: Cheap Drywall screws are fine for the vast majority of projects. Mostly the head type is personal preference, and if you want to pay 2x+ for torx.
I've been using dry wall screws for many many years, 50 years. I have found that there are diff qualities of dry wall screws. ordered cases of cheap over seas stuff and had them snap off when installing them while american made screws don't. Next, I buy "icebit" #2 that are specifically designed for dry wall screws. they don't slip like the one you were using. I also use a slip driver cover with magnet to prevent slipping off the screw. I use a dimpler bit when working with dry wall. Dry wall screws are designed for "drywall". they sink just below the surface while still holding the paper with out tearing it. again specific use screws. I've used them in making hardwood cabinets and found that if I predrill and counter sink them, that they work better than most other types of specialty screws. I use plugs or putty to fill them. Pre-drilling them prevents the "space" between boards. the "lead" on dry screws vary depending on what you buy. Big box stores only carry the most common "lead" sizes. I've worked all the screws that you show and have found that the dry wall screw is the most versatile screws around. I've installed self tapping drywall screws through drywall into steel, so yes, you can buy self tapping dry wall screws. when working with steel sheet metals I like the Teks brand due to the head size. I have removed 50 year old drywall screws in wet locations with out problems, while the same deck screws broke and were rusted. I have removed yellow const. screws that many broke due to rust. Hard to guess which is better???? good video, but I don't agree, use the correct fastener for the application. Friends do encourage friends to buy sheet rock screws....
I used those yellow deck screws to build a swing set with a play house on one side. About 7 years later took it down since the kids were too old for it. I was horrified that those big box store yellow deck screws were so corroded most broke like toothpicks.
The first project I did in my garage was shelves similar to what you're testing. Used drywall screws just like any proper new home owner with his first power drill. Put 3 to 4 screws in each end and 13 years later they're still great. They've held a lot of weight including paint cans, a 5 speed transmission, and me climbing on them. I'd use construction or deck screws now for the torx head, but the drywall still did well
Clear and comprehensive. Nice job. Your experiment, as stated, tested primarily shear; my experience with drywall screws is that they can fail in twist, that is, the head twists off when overdriven in dense woods. This hasn't happened with less-brittle screws.
I've personally had more drywall screws shear off or rust in the wild. It's my own personal experience that has led me to use GRK construction or structural depending on the job. Ive decided to leave drywall screw in the drywall.
The CEE thread of the GRK screw increases the bore diameter prior to seating the head. This is meant to help reduce splitting in the wood when driving the head below the surface.
If you’re doing a lot of this or need multi use heavy duty screws regularly. I think the best value is to get the biggest size container of the grks. The $75 dollar one. With the handle.
my 2c: If you are going based on price, which I feel many new woodworkers are, you can get 2 Drywall screws or 1.5 of the middle 2, for less than the price of 1 GRK. Can the GRK hold up vs multiples of the other types. Basically, would it be better to buy deck screws (as you said you liked) and put 3 in, or 2 GRKs for the same price.
I used deck mate forever in my outdoor furniture. Then I switched to grk and they seem to hold longer, less movement after long periods of use and it might just be me but feel nicer to drive in. I use the tan coated ones and now use them on everything from planters to Adirondack chairs and tables. Good video! Project farm does some good screw tests and some of your information filled in some of his.
Great video Brad. In my opinion don’t screw yourself over the options. If you’re doing a project, just find the right screw for that project. And that’s counting for your budget & what you have on hand for that particular project.
The trick is to have both in your shop. Use the cheap drywall screws for most DIY applications, and save the structural screws for where the strength is truly needed.
Thanks Brad... You should mention that screws for use in treated wood should have a special coating that prevents corrosion from the preserving chemicals.
I’ve done some “real” testing, under true lab conditions, as well as having built many projects using all of these screws. Here are my thoughts: - Drywall screws, all snobbery aside, are perfectly fine for most projects. Their point starts the screw easily, the (coarse) threads grip wood extremely well, and the bugle head easily sinks flush with most materials without needing a countersink. In every way they are superior to traditional wood screws. - The “fancy” screws address the areas where drywall screws can be improved. They have head profiles - Robertson (square) or Torx (star) - that are better held by the driver bit. The plating results in greater corrosion resistance. - The real problem with drywall screws is that not all drywall screws are alike. With these screws the heat treatment they receive during manufacture is critical Generic brands often have poor quality control, resulting in many screws being so hard they become brittle. Others are so soft the driver bit chews up the screw head recess. The cheaper screws also have poorly shaped recesses that keep you from getting a good grip with the drive bit. - While there are “generic” drywall screws, nearly all of the “fancy” screws are made by companies that are proud of their product. The manufacturers make subtle differences in the screws’ design, all intended to make a better screw. The real test is . . . Well, we don’t always use simple lumber. The screw is usually expected to pierce or grab materials such as plywood, chip board, Masonite, even sheet metal.Pressure-treated wood challenges the simple drywall screw with the corrosive chemicals used in treatment.
15:56 second comment lol. I have found that drywall screws are typically harder to drive than construction/deck screws with a Phillips drive. I personally hate Phillips, but i help my brother a lot and it’s what he buys. Using 3- 3 1/2 inch exterior screws is a lot easier than 3 inch drywall screws
Ive used Phillips head screws for over 20 years. Rarely ever had an issue, unless I was in some kind of strange angle, doing a balancing act while driving the screw with one hand tied behind my back. I used torx screws for one summer, and the bits kept slipping, stripping, and shattering 2 or 3 screws out of five each time. I tried different boxes and brands and bits. I finally threw in the towel and figured if I couldn't figure out a technique in 3 months on how to use them correctly, then its not me, its the screws. I went back to Phillips and have never looked back.
I stupidly used to use drywall screws for way too many things. I only use GRK torx head exterior self tapping screws now. During COVID I built a 32'x8' bridge. Because I used these screws I'll be taking it apart and rebuild it over a stream on my property in NH using the same screws as I took out of it.
Agree with some of the folks below. You don't test a shelf by jumping on it! a 170 lb man jumping with all weight directly applied on two small areas where the screws attach puts tremendous pressure on those spots. You would never have this pressure on a normal loaded shelf. I agree with the Phillips head problem vs. Torx though for simplicity and hassle-free installation. Good video.
I remember we all used number 10 nails to put shelves together in our sheds or garage. Not once have I ever had a shelf fail. I have had a shed with shelves for more than 20 years, and not one shelf has fallen or come apart. So what happen to go old nails??
DRYWALL screws were designed for drywall. The head is called a bugle head ad is designed to NOT drill through the paper on the drywall. The cutters under the heads of the other screws would cut the paper the the drywall would collapse. Also, any screws used outdoors on treated wood must be rated for the application. Treated wood is extremely corrosive to metal and will destroy uncoated screws.
It makes me wonder if you pre drilled the hole so the screw didn't act like a wedge splitting the wood and as many said once the first hole was deformed the test went out the window, sorry..!!
I noticed that the construction screws said on the box that they are only for non-structural construction, which I think means they aren't meant for something that bears a lot of weight or force, are there a different type of screw that are meant more for this?
i built my entire deck here using GRK deck screws, has many lag bolts and screws as well for structural supports as well, but honestly, i really like GRK. personally i'd rather spend a little extra for the peace of mind on that, but we all have our preferences when it comes to that. now for shelving, i'd probably save a bit on the money, but since i bought a 5 pound bucket of deck screws for the deck (not knowing how many i would need) i have plenty leftover so i'll use those since i have them. but i'd probably go a little cheaper for a smaller project if i didn't. but like you, i'll definitely stick with torx head screws as i can't stand phillips. now.... square head is ok too, if you already have then on hand, but torx is a no brainer if you're having to buy new
some woods, thicknesses of material, and uses, it doesn't matter, but generally speaking, if you don't pre-drill a hole, your screw will displace more wood. if your wood has a mostly-parallel grain and/or isn't sufficiently thick to compensate, then it's likely to split as a result: compromising your connection strength.
As others have said screws shouldn't hold weight, also though. The types of screws ya are using have different use cases and purposes. Drywall screws are meant to secure drywall to studs, deck screws are designed to secure decks boards to structure in weather conditions meaning they are needing a different protective coating. Same with construction screws. I use what screws I have available then again I am not making furniture to sell and most screws I use are for hanging stuff. All my screws are from shelves or beds or whatever that are broken from kids abusing them or the shelves were cheap and just collapsed after years of use. Screws I kept are all in decent shape, not bent, etc
Personally here in new Zealand I only use tornado often called buggle head or batten screws. They are very similar to the grk apart from that that have 4 sided cutter head. Basically they will punch through pretty much anything without pre drilling
I can see an issue with using these old 2x4s. They're fully dry, new construction grade lumber is slightly wet because it accepts fasteners better. Its possible your results might vary when compared with brand new lumber.
I learned so much! Thanks for the education. Next time I’m staring at the overwhelming number of screws at the big box stores, I may be able to make a more educated choice.
We use the coated deck screws for just about everything and they have to either be Torx or Robertson screws. Phillips screws are absolutely awful and I think they need to go away just like the dinosaurs. We recently redid an old wood fence that has been collapsing in on itself for years. The 4x4 posts were originally notched to take the 2x4 supports and while that may be the correct way to support weight the inner panels were just so heavy that they slowly pulled the screws out of the wood. It didn't help that it's all been rotting over the years so the 4x4's have all twisted where they've been notched. Everything has been done simply without any fancy notches and all of the new wood is a vastly lighter weight than before so it shouldn't be stressing the screws as badly this time around. The fence is to keep in a couple of dogs not a herd of cattle. The old fence was way too over built for its' intended purpose.
I think it would be neat to test whether screws from the top or bottom of an overhead hanging structure have a difference. Is it stronger to screw in from the bottom or the top with equal penetration depth
I believe the self tapping feature is to help prevent splitting the wood by cutting the fibers instead of spreading them around the screw shank, not for starting the screw easier. I think the self tapping feature is more necessary for harder wood, but is still effective on soft wood. You should check out project farm's deck screw video. It's a good one if you want even more comparisons of deck screws.
In hardwoods you don’t want self tappers It’s better to use fine thread screws because the screw isn’t strong enough to not snap The self tapping will cause extra heat and have a higher propensity to snap There’s a separate pilot hole chart for hardwoods where the hole is actually slightly larger and then you’ll use fine thread screws which have an overall slightly narrower diameter This is all so the screw is just barely tapping the wood so it won’t snap the screw Self tapping screws for metal are what you’re referring to. Those will tap the metal once a pilot hole is drilled
Even if the screw is self-tapping, if you're drilling into end-grain, I think drilling even an undersized pilot hole might reduce the probability that the wood might split. In your last test, you had a knot pretty close to the end of your 2x4, and I think that the end of this 2x4 looked pretty weak because of the knot location. It looked like the lumber you used in these tests was pretty low-quality lumber. I believe you live in the south, and so you should be able to get southern yellow pine at your local big box store. If you would have done this test with higher-quality SYP or douglas fir, selected pieces with no knots near the ends with a tight/dense grain pattern, and predrilled pilot holes then I think the screws would have been less likely to pull out. Also, if I'm going to join a couple boards and screw through the face of 1.5 inches of soft wood and then into end grain on the other side, I'd use a 4 inch not a 3 inch screw to get at least 2.5 inches of penetration into the end grain. But you can also buy 1/4" torx-drive lag screws made by GRK or SPAX at the big box store. If I planned to store very heavy items on utility shelves -- like leftover tile or paint cans or heavy tools like my shop compressor -- then I'd probably use 1/4" screws. If I knew that I'd only be storing lighter materials then I might use 4 inch #10 GRKs.
Drywall screws are fine for drywall, but not so much for woodworking. Because they're designed to fasten drywall to wood, not to fasten two pieces of wood together. They don't really need to be super strong, because the drywall itself is far weaker, and lots of screws are used in a sheet of drywall to hold it tight to the studs, which also distributes the weight of the sheet over many attachment points. The other screws are designed to hold two pieces of wood together, so their features are all geared to that, and they're stronger than drywall screws. Personally, the only failures I've had in drywall screws have been from twisting; if I dry to drive them into wood and meet resistance, assuming they don't cam out, the heads twist right off. Better to go with wood screws when fastening two pieces of wood together, especially if you intend the attachment to hold more than the weight of the wood itself, such as in shelves or furniture. The safety factor is worth spending the extra money on.
I have used drywall screws for say hanging pictures on a wall or something like that. If you breathe on the me moisture in your breath will rust them. There is a brand of decking screw sold at Lowes (a place I hate but only place that sells the screws) that are kind of the best. Not cheap but I have a large stash of just about every size. Phillips screw heads in anything bigger then eyeglass screws are completely worthless. If you can't get Torx heads at least got with the second best, and Allen head.
I'm definitely a firm believer in glue to do all the work, screws to hold while the glue dries. That, or use wooden vertical supports under the shelves to bear the weight instead of just screws. There is definitely a purpose for screws and fasteners, but not for ultimate weight bearing like shown here. Still a useful test and showed that junky screws can hold an entire person (before jumping).
I used drywall screws in all my custom woodworking projects for years until a few years ago when they got up to $6.00 for a pound box at the big box stores. I had previously used square drive screws at the cabinet shops ive worked it and Ive loved them from day one! I finally decided if I was gonna pay $6.00 for a box of screws, I might as well change over to all square drives. I buy Hillman square drive screws from Amazon now and at about 5 cents a screw (depending on screw length)...well, its a no brainer!
The bottom line: Buy the screw defined by code for the project. No one should try to "make do" with cheap materials. Quality outcomes are a result of quality materials used in the first place.
Star drive, or square drive for me if I'm given the choice. Overall, Philips head are usually crap when driving for depth. Although little screws for drawer slides, and such then the Philips heads are fine, and are usually the only option anyway. A fun video, Thank you.
Interesting, but far from a series of controlled tests leading to a number of variables which introduce inconsistencies. At best a rule of thumb result. The best aspect is showing the differences in screw design and what that may mean with some given uses.
It would be interesting to know if there is any steel recipe difference between the screws. And I don't even know why they still make phillips head, I've always hated them, but the quality of the driving tool and the applied force into the head can make them acceptable just barely. Even square drive is better.
I've seen some cheap garby screws just snap (close to the head) while fastening/taking them out of simple things like plywood, cement board, etc. And it isn't just a one time thing either.
With the Phillips screws, it's not just the angle, but the speed that you drive with. A driver, like you're using, will drive the screw faster than you can keep up with - pulling the bit out of the screw just enough to dis-engage. Add this to the angle between the bit and the screwhead, and it's very difficult to keep the two engaged.
You must also consider the type of load applied. What you did (stomping) is a DYNAMIC (rapidly changing) load, that is one type. The second type is a STATIC load. This is where a load is applied "gently" incrementally. These tests WILL show different results.
I use coarse thread drywall screws all the time for internal stuff. Pre drill, and run them in. They hold just fine. I have shelves that are holding 100s of pounds in the garage assembled this way. External stuff? Yeah, use exterior rated screws to avoid rusting out. I still pre drill to avoid splitting shenanigans.
screws are really only good for clamping force, if you want to put them under a sheer load then nails (in the case of construction with lumber) tends to work much better due to the engagement with the wood and how they are made
I'm curious... since the GRKs are 2.33x the cost of the drywall screws... what if you doubled up on the dry walls? So compare 4 GRKs to 8 drywall screws. You'd be saving 2.8¢ per fastening, but obviously at the cost of more labor to pilot drill and drive. Maybe there's a better ratio than 2:1... 3:2 or something? (3 drywalls would be 24.9¢, 2 GRKs would be 38.8¢)
Too many times I've had drywall screws snap off just at the last moment, leaving the body of the screw in my workpiece, basically irretrievable. I'll never use for anything important, and the ones I have left will be for shop jigs only.
12:00 "Tensile Strength" vs. pulling "Shear Strength" vs. uuuuuh.... _shearing..._ 😅 "Torsional Strength" vs. twisting "Flexural Strength" vs. Bending (aka 'stiffness') Last, but not least: "Compressive Strength" vs. squishing
Go watch Project Farm's video on screws & nails.
This video is how to do a bad test, and build something wrong.
If all the weight is on ANY screw or nail it's dangerous.
Fasteners hold lumber and brackets. Lumber holds the weight.
I don't think this video was about what is the right way to build something, in fact the other video he references shows the right way to build a shelf for example.
In this he was only testing what would happen to the screws. He wouldn't be able to do this test if he built a proper shelf because the blocking would take the weight and stress.
@@procrastinatingnerd but that isn't how screws work. The screw is not strong against shear forces, because it is not designed for that. The screw in this case is supposed to pull the vertical and the horizontal pieces of wood together, and the friction between the two surfaces caused by the screw pulling those two surfaces together should hold it up.
He isn't testing what would happen to the screws or how good those screws are. He is testing what happens to those screws if you are using them wrong enough (which he does).
@@edededededededededede He wasn't just testing the screws shear breaking force, this simple test showed the differences between the screws in a simple way. He was also testing the thread holding strength which DOES make a difference in how tightly the screws can hold the surfaces of the wood together and maintain that friction.
I get some of what your saying, this wasn't a real world test for the screws, but by your logic, it truly wouldn't matter what screw is used because if the thing being built is built right then any of these screws would work. But this wasn't to test just that. He actually had a few different tests in this video. For example he confirmed for everyone that Philips head screws are a terrible choice for this application. That has nothing to do with the screw strength.
Using the screws wrong enough will tell you a lot about them!
There are screws that are made to take weight, they are called structural construction screws. Look on the box, it will tell you if they are for structural or non-structural usage. You should know with how you are building and assembling a project if you are making the screw support any weight. If the fastener does take weight make sure the box specifies structural usage.
Came here to say the same thing about watching Todds (Project Farm) videos. Todd is very scientific about his approach so that he doesn't influence anything. (Also, regarding proper way to built something, or whether or not the screws are meant for this type of force is somewhat irrelevant. It's true, however, this is more of a what if they did receive that type of force? It's a great video idea for most people building some quick shelving in their garage, house, etc.)
Big problem with your testing, you kept reusing the same hole in the vertical board, the very first screw distorted the hole and made every screw after that to bend down and easily pull out of the wood. In other words, you should have used a new hole each time. See angle of screws on uprights at 3:28
Agreed. Also seems he was going into the same hole on the horizontal piece too. Bad test.
I noticed the same thing, and I agree with you.
Project Farm would have used a whole new rig for each test. Sorry Brad 😁😁You're still awesome, though.
Brad is not a carpenter and this test shows how lack of knowledge can affect outcomes.😂
also stomping is not a very even application of force nor the same amount each time, and then consider the differing weakness of wood given the screw location. I would have been happy with the general test itself if he didn't give an actual conclusion
The testing is also aimed at shock/shear strength. Lumber fasteners seldom fail in that manner. You should be testing the fasteners ability to deform (bend) without failing. Imagine an old barn that just wants to lean over.
From a physics perspective, there is an incredible difference between static load and kinetic force. A more reasonable test is you adding weight gently until the joint fails. The torque of the stomping is essentially thousands of lbs vs the real weight it can hold with is a 1000 lbs.
I feel like nobody's watching the video all the way through. He goes on to explain the different types of loads.
I agree with you in general, but sometimes if you're placing something very heavy -- like a crate full of tile or some cement blocks or a benchtop drill press -- onto shelving, you might lose your grip and accidentally drop your load onto the shelf from a few inches above the shelf.
So sometimes shelving and decking have to withstand dynamic loads not just static loads.
@@clutteredchicagogarage2720 Yes, although most people aren't going to be dropping their entire bodyweight from a foot or two up.
To do a fair test, you should drill new holes for each test
Torx head screws cured my PTSD and allowed me to fire my psychiatrist. 😃
I'm old enough to remember the transition between straight/slotted drive screws to Phillips, Phillips to Roberts, and more recently, Torx. Each one was an improvement over the preceding drive type, but Torx is by far the least frustrating. I recall working on crews and hearing that all-too-familiar sound of a Phillips bit losing it's bite and stripping out the head of the screw. Finding a decent quality Phillips driver bits was always something I was bent on improving, and even with good quality bits, one HAD to provide PLENTY of force into the screw to keep the bit engaged AND have them aligned almost perfectly. Now that Torx is on the scene, yeah they're more expensive, but they're also saving time and frustration, and that is not so easy to put a dollar value on.
I'm old enough too. I think that we forget that Phillips screws were designed when power tools were not even a twinkle in someones eye. Sure they cam out quickly when you put power to them, not so much when you use a screw driver. They are just old technology that we don't seem to be able to move on from. Me, I'm a Roberts fan all the way (thank Kreg tools for setting me on that path) but I'm quickly coming around to Torx, specifically GRK. Love that wide washer head on the larger ones.
Agree, Torx scews are superior to Phillips , but you still get the same problem with angle etc, if the torx bit is worn.
Worse, Robertson screw heads were invented before Phillips, but Ford screwed us.
I don't know how many times that I have stabbed myself with a Flathead or a Philips screwdriver and it hurts, Torx screvdrivers minimize this unless the bitsize is small enough but then I am working with electronics and not woodworking so the risk is already minimized because most often the forces is less. but sure I have stabbed myself doing electronics when the screws are really stuck too 😅 at that scale it dosn't matter what kind of bit you use, them all will penetrate your skin
Phillips screws are DESIGNED to cam out. If you ever install drywall/sheetrock you will see how this works. I am pretty sure they were designed that was for use on aircraft so they would not be over tightened. (check this as I have not researched it so it's just a rumor)
Okay, playing chords when you showed Dmaj and Dmin was pretty clever.
Also, I know that this wasn't meant to be one, but for a scientifically accurate test, you'd need to make some changes to the set up.
1. Use a machine to apply the load. This can be a jack, a screw, or something else. It just needs to be able to apply a consistent load to the test article.
2. Use something to measure the force applied. It should have a way for you to measure and record the peak force, since that'll be force at which you suffered a failure.
3. Try to keep from changing more than one variable at a time. There's a few things to consider here. The pilot hole, the shank diameter, the cut (geometry) of the screw thread, the major and minor diameters of the thread, the pitch of the thread, the material of the screw, the number of screws, the spacing of the screws, and the composition of the boards used to make the structure. All of these are going to affect the performance of the screws. As some have pointed out, the hole that you put the screws into was the same hole, and it was changing with each test.
4. There's a difference between shock loads, dynamic loads, and static loads. Jumping on the test rig generates a shock load. This applies a lot more force to the structure for a given mass. Force is mass times acceleration, and you're going from several meters a second to 0 in a very short amount of time.
Dynamic loads change over time. This is what you have when you gradually increase the force applied until something fails. This is a good way to test when you've hit the physical limits of a connection and figuring out how much something can hold given a specific safety margin or factor. (If you want a 2 times safety factor, you'd take the force that the structure failed at and divide by 2.)
Static loads don't change over time, but the thing is, everything is plastic given a fine enough resolution (i.e. accuracy of measurement) and enough time (on the scale of millions of years, stone and rock are very much plastic.) Applying a static load over time can tell us how the connection will perform over time. Sure, it might be able to resist a given force that's slightly less than the force needed to cause a failure, but you're stressing the wood and the screws a lot. Over time, that stress can lead to a failure as it causes the wood and the screws to deform. This is why something might hold for a while then fail suddenly even if the force being applied hasn't changed at all. Something deformed enough to change how the force is being applied and transmitted through the structure.
Incidentally, this is also another thing that is affecting your tests. When you jump on it, you're not going up to the same height above the shelf every time. It's always going to be a bit different. Similarly, you're also not landing in the same place each time, which is going to affect the amount of force you're actually applying to the screws. The further from the connection you land, the more leverage you have and thus the more force you're applying to that connection.
So, if you want to really see which is better for a given application, you'd need to change the setup to control as many variables as possible. Some things, like the structure of the boards (i.e. the wood grain, moisture content, microcracks and splits, etc.) are going to be almost impossible to control for, but you can still get a pretty good idea of how the screws perform by doing multiple tests and using statistical analysis to get an idea of how well the screws are doing even if there are things you can't control affecting your results.
The downside of this, is that it's going to take a lot of boards to do this right since each test will need to be done with with new boards that are part of the connection you are testing at the very least. Don't forget that you also have to worry about the boards transmitting the forces and loads to the connection. As you stress them, they can also change enough to affect the results of your testing.
Screws work to setup but not support. Use braces, brackets, blocks, notches for support and strength.
Screws are strong in the dimension along their length, not in shear. But if the material is strong enough, the clamping force of the screw creates enough friction to take care of the shear force. So with the right material and screw placement, screws can absolutely be all you need.
@@pilotdog68even lag bolts if able 👍🏻👍🏻
Drywall screws have a bugle head, designed to gently compress drywall paper without tearing. Used in wood or sheet goods they work like a wedge and split them open easily. And in drywall screws, cam-out is a feature that every screw gun makes use of to help set the proper depth.
2:08 remember the days when finish carpenters drilled pilot holes? Believe it or not, if done right, pilot holes can add strength. You’re removing the internal tension in wood imposed by just driving them straight in.
5:50 difference between #8 & #9 # 10 is approximately 8% between
Facts. Pre-drilling saves lumber and increases strength. Short-cuts lead to increased costs, and damages.
I don’t know that building shelves for the garage requires finish carpenter level of detail. This whole video is a little silly. 🤷♂️
@@ScottFidler I don't think it requires finish-level carpentry details, but if you're going to put heavy stuff on the shelves and you're bothering to allocate the time to building them, you might as well overbuild them so you never have any issues.
For me, spending an extra 30 minutes of time on construction is never an issue. The issue for me is always taking time out of my day to get my tools together for a job, run to the hardware store to buy screws + other materials (and lumber), etc.
So if it takes me an extra 30 seconds per hole to drill a pilot hole and I spend an extra 10 minutes building something, the added time is negligible.
Similarly, for me, spending 20 cents per screw vs 9 cents per screw doesn't matter at all. It matters for some people, but I can afford a premium screw, and I'd rather pay for a nicer screw that uses torx drive, pulls my wood together well, etc.
What wasn't discussed in this video is that I am fully convinced that spending extra time at the lumber yard or hardware store to pick out the best pieces of lumber in the pile can have a huge impact on the strength and stability of your project. I'm not talking about using white oak or some kind of expensive wood. I'm talking about simply picking out 2x4s from the pile that don't have large knots, aren't already splitting, are straight, and have relatively tight growth rings/grain.
@@clutteredchicagogarage2720 A lot of my shop infrastructure is built using furring strips. You can bet I pre-drill/countersink all the holes in anything one-by I use. Two-by I usually only do that at the ends, they don't usually split in the middle.
My house was built in 1996 with a cheap construction-grade wooden attic ladder in the garage ceiling. In 2001 I had a contractor replace the ladder with a higher grade wooden stair unit. I did not pay attention to what he was using to secure the ladder's box frame to the ceiling joists (turns out it was drywall screws!). Forward to 2016, I hired a company to replace my A/C unit in the attic which meant there was sometime two guy plus the weight of the equipment going up and down that ladder. I did not think anything of it as I had been running up and down that ladder for 15 years. As soon as the workers hauled the last piece of the new A/C unit up into the attic, I decided I would climb up there a few minutes later to see how it was going. I got about half way up the stairs when "crash!" - the whole attic stair frame (with stairs attached) fell out of the ceiling!!! Tore me up somewhat and messed up my back, but a miracle it did not kill me! One step higher and that would have done it. After investigating what happened, it was found that the frame had been fastened to the joists with those black/brittle drywall screws and they just sheared off (threads did not pull out). Worked fine for the first few years luckily, but finally failed catastrophically. Thank God they held long enough for those workers to get that A/C unit up there or I would have had two dead workers and a terminal lawsuit on my hands! Went back with heavy construction screws.
mathias wendall has entered the chat. Drwall screws are great for 90% of what I do. I've never had a screw "fail". But that's just my limited experience. For outdoor stuff I use the 3" Grip Rite #9 Exterior Screws.
I kept thinking about him during this "experiment"....he's pretty much the gold standard with YT woodworking testing
Many sources in print and online say that choosing the correct wood screw requires having only smooth shank with no threads in the workpiece "on top" (i.e. closest to the screw's head) so that as it's tightened, it pulls that workpiece against the one in which the threads are embedded. Some drywall screws have threads all the way from the head to the tip and some only have a short unthreaded area. If there are threads in both workpieces, then driving the screw doesn't pull them together but rather moves them both in unison. Isn't that enough reason not to use drywall screws for anything but drywall?
I started using the GRK screws and I’ve never looked back. Highly recommend them.
Absolutely love the GRK screws.
They be pretty
So in the final test you made an error. with the GRK screws you put them vertically, which put each screw into different parts of the grain making the force spread across the wood better. and with the construction and drywall screws, you put them horizontally, making them go into the same grain section causing the wood to fail more easily. Also, one thing you didn't mention is the design of the drywall screw head is not to be countersunk into wood. the curved shape as well as the smoothness is to allow the head to countersink into drywall without tearing the paper, and that is why they hold so well.
All in all, a good video, and definitely interesting to see how each screw held up to a test like that.
Its a game of surface area, some screws are meant to be used in softer surfaces, meaning they distribute their weight more with the shape and thread. Obviously material plays a part, but in most cases if your screws are breaking you have a different problem.
You needed new holes for each screw in my opinion because of the enlarged hole in the back of the board where screws had already been pulled down. I think that gave the screw room to move more than a fresh hole would have.
Screws are not for weight structure unless otherwise specified and specced for. All screws are good, it's how you use them that makes them bad or not.
"specified and specced for"
Most things people build do not have engineered plans.
@@pilotdog68 You really don't need engineered plans, just read on the box. It will tell you if they are for structural or non-structural usage. You should know with how you are building and assembling a project if you are making the screw support any weight.
when i started building more things within the last year, I bought drywall screws at first because I liked the flat black look. I broke them just below the head over and over trying to sink them without pre-drilling a relatively wide hole, and also trying to drive them flush or below flush. I started buying deck screws and have had zero issues. It's super easy to bore through anything with those and I've had zero failures.
Another option I like is cabinet screws for a clean look if the screws are going to be visible, and I trust them not to break like the drywall screws. Pocket hole screws are also a great pan head alternative and I've been using them more in certain situations after watching your base cabinet videos. Built my first cabinet ever just a few weeks ago and thanks to your videos and clear explanations, it turned out great!
Inappropriate use of screws.
When I built shelves in my utility room, I cut 3/4" dados in the upright 2x4s and used 3/4" plywood ripped down to 2' wide for the shelves. I only used screws to mount to the wall and to hold the shelves in the dados. The weight is held by the 2x4 wood uprights. After 30 years they are still solid.
I swapped out drywall screws once I started doing a lot of outdoor work. The coated or stainless screws are still the best bet for preventing rust spots.
Drywall screws are not authorized for support construction per building codes in 50 states. I.e. Joists, load bearing walls, must be construction grade or you can expect to unscrew every drywall screw and replace them or receive no reimbursement from insurance companies and building condemned by every city ordinance inspector. Fasteners (those things attached to load bearing construction) can be any material (plastic, stick-ums, drywall screws). For shelving, since they are non load bearing use joinery or brackets off the load bearing structural supports. Or just do what you want and live with the consequences... that is what I would prefer but since I so lots of construction and research building codes for every damn city i find myself in, the ordinance codes are where you want to start. Remember: Fasteners are not load bearing.
My experience as a carpenter is that there are huge differences between screws, but the price is often not a indication of quality.
Buy known brands that have a reputation to preserve, since then the quality is often good throughout the lineup.
The largest difference between good and bad screws are the corrosion resistance, and the second thing is the overall strength. Screws need to be just stiff enough, but at the same time be able to bend without snapping. let's say you have a huge snowfall or powerful winds that make some of the screws break. You will have a huge problem over time.
Since nails are rarely used anymore and we almost only use screws I buy screws by weight or in large quantities as 1000pcs boxes.
Square head srews are better than the torx head. Even though I have plenty torx screws of many sizes, I am slowing switching over to square head screws. Would like to see a comparison test.
I always use deck screws, Brad. The lack of a smooth shank under the head of drywall screws means the hole in the outer piece needs to be larger than the thread. For drywall, it's not necessary because the drywall just crumbles. Also, in my younger days of woodworking, I snapped many drywall screws while tightening them.
Bill
23:38 Am I flocking missing something here because I see two dry wall screws behaving the same as the expensive ones despite the voice over conclusion that says the opposite??
Great Video, Someone may have already said this, but I'll add it anyway! For the shear force case, the diameter of the screw isn't what's important. In a shear force case, you care about the friction force between the two surfaces (Created by the screw pulling them together). That friction force is where the strength comes from. The item will fail when you get slippage and a shear force acts on the screw (Which they are not designed to resist).
This also means it's really important to create a high force between the two surfaces (Your pre-load) before the screws are put in to fix them.
If you do this test again I would clamp the two surfaces together first, then screw them, I think you'll get much better results.
For more info look up "Bolted joint design". Keep up the great work!
Obligatory Canadian comment: I'm so glad you're calling out the awfulness of Philips here, but have you ever gotten a chance to try Robertson (or squarehead as it's sometimes known)? It's a particularly good option, and is the best I've ever used.
I made tons of cool stuff with drywall screws because there was a buttload of them in my garage when we bought our house. I never had a problem and they worked great. I even bought more when I ran low on them. They actually sell some with self-tapping tips of different designs.
Then, there were some projects that were basically just toys for the kids that got left outside. They stayed together perfectly fine but when I disassembled them to either fix stuff or use the wood for other projects, they were already trying to rust to death. I never had a failure because there weren't any screws that were critical components but it definitely let me know that this wasn't the proper application for them.
However, if I were building something that I knew was staying inside and I only had a box of drywall screws, I wouldn't hesitate to use them.
They don't seem to do great being driven in with an impact but a standard drill seems to do fine with them.
1. So this testing wasn’t perfectly engineered. It was VERY informative. Great video!
2. Drywall screws and many others with dubious coatings are dangerous in exterior or otherwise corrosive applications. I used drywall screws to assemble an outdoor shed which was then painted. After a decade exposed to weather, the drywall screws literally disintegrated and disappeared beneath the paint. Same would be true of every other screw with a cheap, thin coating including electroplated zinc.
3. Among reasons for using screws is disassembly. If paint is applied to surfaces, embedded screw heads become difficult to locate and are clogged, making disassembly nearly impossible. Screwed assemblies can’t be pried slightly to locate & expose screws for removal without causing damage. Nails aren’t so bad. They often make prying and non-destructive disassembly possible.
Was never meant to be a controlled scientific test, should have been more clear on that. But glad you enjoyed the info!
Glue and screw. Pilot holes always.
Good wood glue and plenty of dry time would certainly help strengthen the shelves.
Stumpy Nubs has a similar comparison. TL;DR: Cheap Drywall screws are fine for the vast majority of projects. Mostly the head type is personal preference, and if you want to pay 2x+ for torx.
I've been using dry wall screws for many many years, 50 years. I have found that there are diff qualities of dry wall screws. ordered cases of cheap over seas stuff and had them snap off when installing them while american made screws don't. Next, I buy "icebit" #2 that are specifically designed for dry wall screws. they don't slip like the one you were using. I also use a slip driver cover with magnet to prevent slipping off the screw. I use a dimpler bit when working with dry wall. Dry wall screws are designed for "drywall". they sink just below the surface while still holding the paper with out tearing it. again specific use screws. I've used them in making hardwood cabinets and found that if I predrill and counter sink them, that they work better than most other types of specialty screws. I use plugs or putty to fill them. Pre-drilling them prevents the "space" between boards. the "lead" on dry screws vary depending on what you buy. Big box stores only carry the most common "lead" sizes. I've worked all the screws that you show and have found that the dry wall screw is the most versatile screws around. I've installed self tapping drywall screws through drywall into steel, so yes, you can buy self tapping dry wall screws. when working with steel sheet metals I like the Teks brand due to the head size. I have removed 50 year old drywall screws in wet locations with out problems, while the same deck screws broke and were rusted. I have removed yellow const. screws that many broke due to rust. Hard to guess which is better???? good video, but I don't agree, use the correct fastener for the application. Friends do encourage friends to buy sheet rock screws....
I used those yellow deck screws to build a swing set with a play house on one side. About 7 years later took it down since the kids were too old for it. I was horrified that those big box store yellow deck screws were so corroded most broke like toothpicks.
The first project I did in my garage was shelves similar to what you're testing. Used drywall screws just like any proper new home owner with his first power drill. Put 3 to 4 screws in each end and 13 years later they're still great. They've held a lot of weight including paint cans, a 5 speed transmission, and me climbing on them. I'd use construction or deck screws now for the torx head, but the drywall still did well
Clear and comprehensive. Nice job.
Your experiment, as stated, tested primarily shear; my experience with drywall screws is that they can fail in twist, that is, the head twists off when overdriven in dense woods. This hasn't happened with less-brittle screws.
I've personally had more drywall screws shear off or rust in the wild. It's my own personal experience that has led me to use GRK construction or structural depending on the job. Ive decided to leave drywall screw in the drywall.
Exactly this. Especially if you have a 100-year-old house with very hard studs. The black screws snap right off.
@@russmathis3549 mine is 124 years right now.
The CEE thread of the GRK screw increases the bore diameter prior to seating the head. This is meant to help reduce splitting in the wood when driving the head below the surface.
If you’re doing a lot of this or need multi use heavy duty screws regularly. I think the best value is to get the biggest size container of the grks. The $75 dollar one. With the handle.
My collection of GRK screws just keeps growing. Love those things
my 2c: If you are going based on price, which I feel many new woodworkers are, you can get 2 Drywall screws or 1.5 of the middle 2, for less than the price of 1 GRK. Can the GRK hold up vs multiples of the other types. Basically, would it be better to buy deck screws (as you said you liked) and put 3 in, or 2 GRKs for the same price.
I used deck mate forever in my outdoor furniture. Then I switched to grk and they seem to hold longer, less movement after long periods of use and it might just be me but feel nicer to drive in. I use the tan coated ones and now use them on everything from planters to Adirondack chairs and tables. Good video! Project farm does some good screw tests and some of your information filled in some of his.
Great video Brad. In my opinion don’t screw yourself over the options. If you’re doing a project, just find the right screw for that project. And that’s counting for your budget & what you have on hand for that particular project.
The trick is to have both in your shop. Use the cheap drywall screws for most DIY applications, and save the structural screws for where the strength is truly needed.
Thanks Brad... You should mention that screws for use in treated wood should have a special coating that prevents corrosion from the preserving chemicals.
I’m just impressed with how many times you said shank, screw, and pull out without a single innuendo. I hope to be half as mature as you one day
You can't imagine how many times I said shaft and then did a retake to say shank just to keep from laughing 😂
I’ve done some “real” testing, under true lab conditions, as well as having built many projects using all of these screws. Here are my thoughts:
- Drywall screws, all snobbery aside, are perfectly fine for most projects. Their point starts the screw easily, the (coarse) threads grip wood extremely well, and the bugle head easily sinks flush with most materials without needing a countersink. In every way they are superior to traditional wood screws.
- The “fancy” screws address the areas where drywall screws can be improved. They have head profiles - Robertson (square) or Torx (star) - that are better held by the driver bit. The plating results in greater corrosion resistance.
- The real problem with drywall screws is that not all drywall screws are alike. With these screws the heat treatment they receive during manufacture is critical Generic brands often have poor quality control, resulting in many screws being so hard they become brittle. Others are so soft the driver bit chews up the screw head recess. The cheaper screws also have poorly shaped recesses that keep you from getting a good grip with the drive bit.
- While there are “generic” drywall screws, nearly all of the “fancy” screws are made by companies that are proud of their product. The manufacturers make subtle differences in the screws’ design, all intended to make a better screw.
The real test is . . . Well, we don’t always use simple lumber. The screw is usually expected to pierce or grab materials such as plywood, chip board, Masonite, even sheet metal.Pressure-treated wood challenges the simple drywall screw with the corrosive chemicals used in treatment.
Generally, sheer strength is better in nails than in screws
15:56 second comment lol. I have found that drywall screws are typically harder to drive than construction/deck screws with a Phillips drive. I personally hate Phillips, but i help my brother a lot and it’s what he buys. Using 3- 3 1/2 inch exterior screws is a lot easier than 3 inch drywall screws
Thanks for always having great content
Our pleasure!
I need to attach a 1/2 inch board to the wall and stud, which screw do you recommend, and what size? thanks
Ive used Phillips head screws for over 20 years. Rarely ever had an issue, unless I was in some kind of strange angle, doing a balancing act while driving the screw with one hand tied behind my back. I used torx screws for one summer, and the bits kept slipping, stripping, and shattering 2 or 3 screws out of five each time. I tried different boxes and brands and bits. I finally threw in the towel and figured if I couldn't figure out a technique in 3 months on how to use them correctly, then its not me, its the screws. I went back to Phillips and have never looked back.
I stupidly used to use drywall screws for way too many things. I only use GRK torx head exterior self tapping screws now. During COVID I built a 32'x8' bridge. Because I used these screws I'll be taking it apart and rebuild it over a stream on my property in NH using the same screws as I took out of it.
Wow!!!! Alot of homework went into this video!!!!! Very appreciated!!! Thanks for all the great info and all you put into it!!!
Agree with some of the folks below. You don't test a shelf by jumping on it! a 170 lb man jumping with all weight directly applied on two small areas where the screws attach puts tremendous pressure on those spots. You would never have this pressure on a normal loaded shelf. I agree with the Phillips head problem vs. Torx though for simplicity and hassle-free installation. Good video.
I remember we all used number 10 nails to put shelves together in our sheds or garage. Not once have I ever had a shelf fail. I have had a shed with shelves for more than 20 years, and not one shelf has fallen or come apart. So what happen to go old nails??
DRYWALL screws were designed for drywall. The head is called a bugle head ad is designed to NOT drill through the paper on the drywall. The cutters under the heads of the other screws would cut the paper the the drywall would collapse. Also, any screws used outdoors on treated wood must be rated for the application. Treated wood is extremely corrosive to metal and will destroy uncoated screws.
It makes me wonder if you pre drilled the hole so the screw didn't act like a wedge splitting the wood and as many said once the first hole was deformed the test went out the window, sorry..!!
I noticed that the construction screws said on the box that they are only for non-structural construction, which I think means they aren't meant for something that bears a lot of weight or force, are there a different type of screw that are meant more for this?
I think some people forgot why he was testing this....the specific type of shelves being built.
I don't use drywall screws, simply the heads break off, construction of deck screws for me. love the Torx heads, drywall stripping the Philips drive.
i built my entire deck here using GRK deck screws, has many lag bolts and screws as well for structural supports as well, but honestly, i really like GRK. personally i'd rather spend a little extra for the peace of mind on that, but we all have our preferences when it comes to that. now for shelving, i'd probably save a bit on the money, but since i bought a 5 pound bucket of deck screws for the deck (not knowing how many i would need) i have plenty leftover so i'll use those since i have them. but i'd probably go a little cheaper for a smaller project if i didn't. but like you, i'll definitely stick with torx head screws as i can't stand phillips. now.... square head is ok too, if you already have then on hand, but torx is a no brainer if you're having to buy new
Thanks for all the testing and comparison, Brad! 😃
Really interesting results!!!
Stay safe there with your family! 🖖😊
some woods, thicknesses of material, and uses, it doesn't matter, but generally speaking, if you don't pre-drill a hole, your screw will displace more wood.
if your wood has a mostly-parallel grain and/or isn't sufficiently thick to compensate, then it's likely to split as a result: compromising your connection strength.
As others have said screws shouldn't hold weight, also though. The types of screws ya are using have different use cases and purposes. Drywall screws are meant to secure drywall to studs, deck screws are designed to secure decks boards to structure in weather conditions meaning they are needing a different protective coating. Same with construction screws.
I use what screws I have available then again I am not making furniture to sell and most screws I use are for hanging stuff. All my screws are from shelves or beds or whatever that are broken from kids abusing them or the shelves were cheap and just collapsed after years of use. Screws I kept are all in decent shape, not bent, etc
Personally here in new Zealand I only use tornado often called buggle head or batten screws. They are very similar to the grk apart from that that have 4 sided cutter head. Basically they will punch through pretty much anything without pre drilling
I can see an issue with using these old 2x4s. They're fully dry, new construction grade lumber is slightly wet because it accepts fasteners better. Its possible your results might vary when compared with brand new lumber.
I learned so much! Thanks for the education. Next time I’m staring at the overwhelming number of screws at the big box stores, I may be able to make a more educated choice.
From my experience, deck screws corrode in as short as a year. I switched to stainless steel which are softer, but never corrode.
We use the coated deck screws for just about everything and they have to either be Torx or Robertson screws. Phillips screws are absolutely awful and I think they need to go away just like the dinosaurs. We recently redid an old wood fence that has been collapsing in on itself for years. The 4x4 posts were originally notched to take the 2x4 supports and while that may be the correct way to support weight the inner panels were just so heavy that they slowly pulled the screws out of the wood. It didn't help that it's all been rotting over the years so the 4x4's have all twisted where they've been notched. Everything has been done simply without any fancy notches and all of the new wood is a vastly lighter weight than before so it shouldn't be stressing the screws as badly this time around. The fence is to keep in a couple of dogs not a herd of cattle. The old fence was way too over built for its' intended purpose.
I think it would be neat to test whether screws from the top or bottom of an overhead hanging structure have a difference. Is it stronger to screw in from the bottom or the top with equal penetration depth
I believe the self tapping feature is to help prevent splitting the wood by cutting the fibers instead of spreading them around the screw shank, not for starting the screw easier. I think the self tapping feature is more necessary for harder wood, but is still effective on soft wood. You should check out project farm's deck screw video. It's a good one if you want even more comparisons of deck screws.
In hardwoods you don’t want self tappers
It’s better to use fine thread screws because the screw isn’t strong enough to not snap
The self tapping will cause extra heat and have a higher propensity to snap
There’s a separate pilot hole chart for hardwoods where the hole is actually slightly larger and then you’ll use fine thread screws which have an overall slightly narrower diameter
This is all so the screw is just barely tapping the wood so it won’t snap the screw
Self tapping screws for metal are what you’re referring to. Those will tap the metal once a pilot hole is drilled
Even if the screw is self-tapping, if you're drilling into end-grain, I think drilling even an undersized pilot hole might reduce the probability that the wood might split.
In your last test, you had a knot pretty close to the end of your 2x4, and I think that the end of this 2x4 looked pretty weak because of the knot location.
It looked like the lumber you used in these tests was pretty low-quality lumber. I believe you live in the south, and so you should be able to get southern yellow pine at your local big box store. If you would have done this test with higher-quality SYP or douglas fir, selected pieces with no knots near the ends with a tight/dense grain pattern, and predrilled pilot holes then I think the screws would have been less likely to pull out.
Also, if I'm going to join a couple boards and screw through the face of 1.5 inches of soft wood and then into end grain on the other side, I'd use a 4 inch not a 3 inch screw to get at least 2.5 inches of penetration into the end grain.
But you can also buy 1/4" torx-drive lag screws made by GRK or SPAX at the big box store. If I planned to store very heavy items on utility shelves -- like leftover tile or paint cans or heavy tools like my shop compressor -- then I'd probably use 1/4" screws. If I knew that I'd only be storing lighter materials then I might use 4 inch #10 GRKs.
Drywall screws are fine for drywall, but not so much for woodworking. Because they're designed to fasten drywall to wood, not to fasten two pieces of wood together. They don't really need to be super strong, because the drywall itself is far weaker, and lots of screws are used in a sheet of drywall to hold it tight to the studs, which also distributes the weight of the sheet over many attachment points.
The other screws are designed to hold two pieces of wood together, so their features are all geared to that, and they're stronger than drywall screws.
Personally, the only failures I've had in drywall screws have been from twisting; if I dry to drive them into wood and meet resistance, assuming they don't cam out, the heads twist right off.
Better to go with wood screws when fastening two pieces of wood together, especially if you intend the attachment to hold more than the weight of the wood itself, such as in shelves or furniture. The safety factor is worth spending the extra money on.
Brad, I really enjoyed watching this one. Learned a good bit about the screws I regularly use to put stuff together. Cool Video.
I have used drywall screws for say hanging pictures on a wall or something like that. If you breathe on the me moisture in your breath will rust them. There is a brand of decking screw sold at Lowes (a place I hate but only place that sells the screws) that are kind of the best. Not cheap but I have a large stash of just about every size. Phillips screw heads in anything bigger then eyeglass screws are completely worthless. If you can't get Torx heads at least got with the second best, and Allen head.
In the past I've had drywall screws snap on way in to wood. Not a fan but will use the for temporary gadgets and jigs
I'm definitely a firm believer in glue to do all the work, screws to hold while the glue dries. That, or use wooden vertical supports under the shelves to bear the weight instead of just screws. There is definitely a purpose for screws and fasteners, but not for ultimate weight bearing like shown here. Still a useful test and showed that junky screws can hold an entire person (before jumping).
I used drywall screws in all my custom woodworking projects for years until a few years ago when they got up to $6.00 for a pound box at the big box stores. I had previously used square drive screws at the cabinet shops ive worked it and Ive loved them from day one! I finally decided if I was gonna pay $6.00 for a box of screws, I might as well change over to all square drives. I buy Hillman square drive screws from Amazon now and at about 5 cents a screw (depending on screw length)...well, its a no brainer!
The bottom line: Buy the screw defined by code for the project. No one should try to "make do" with cheap materials. Quality outcomes are a result of quality materials used in the first place.
Star drive, or square drive for me if I'm given the choice. Overall, Philips head are usually crap when driving for depth. Although little screws for drawer slides, and such then the Philips heads are fine, and are usually the only option anyway.
A fun video, Thank you.
Interesting, but far from a series of controlled tests leading to a number of variables which introduce inconsistencies. At best a rule of thumb result. The best aspect is showing the differences in screw design and what that may mean with some given uses.
It would be interesting to know if there is any steel recipe difference between the screws. And I don't even know why they still make phillips head, I've always hated them, but the quality of the driving tool and the applied force into the head can make them acceptable just barely. Even square drive is better.
I've seen some cheap garby screws just snap (close to the head) while fastening/taking them out of simple things like plywood, cement board, etc. And it isn't just a one time thing either.
You had me at “beefy shaft” 😂😂😂
The concave feature on the screws is help keep the screws from backing out after being set.
With the Phillips screws, it's not just the angle, but the speed that you drive with. A driver, like you're using, will drive the screw faster than you can keep up with - pulling the bit out of the screw just enough to dis-engage. Add this to the angle between the bit and the screwhead, and it's very difficult to keep the two engaged.
Drywall screws have been holding up my kitchen cabinets since 1987. I also pre-drilled the holes.
You must also consider the type of load applied. What you did (stomping) is a DYNAMIC (rapidly changing) load, that is one type. The second type is a STATIC load. This is where a load is applied "gently" incrementally. These tests WILL show different results.
Additionally, the best support is not screws but sheet brackets and 3 galvanized nails/ you will always be inspection pass by using those.
I use coarse thread drywall screws all the time for internal stuff. Pre drill, and run them in. They hold just fine. I have shelves that are holding 100s of pounds in the garage assembled this way.
External stuff? Yeah, use exterior rated screws to avoid rusting out. I still pre drill to avoid splitting shenanigans.
screws are really only good for clamping force, if you want to put them under a sheer load then nails (in the case of construction with lumber) tends to work much better due to the engagement with the wood and how they are made
Are the GRK brand screws part of their sheer screw line?
Why is there a ghost deer at 0:15 ?
I would use drywall screws on the parts with no force on them Ie. Just the chipboard shelf. But use deck / wood screws on the 2x4
I'm curious... since the GRKs are 2.33x the cost of the drywall screws... what if you doubled up on the dry walls? So compare 4 GRKs to 8 drywall screws. You'd be saving 2.8¢ per fastening, but obviously at the cost of more labor to pilot drill and drive. Maybe there's a better ratio than 2:1... 3:2 or something? (3 drywalls would be 24.9¢, 2 GRKs would be 38.8¢)
Too many times I've had drywall screws snap off just at the last moment, leaving the body of the screw in my workpiece, basically irretrievable. I'll never use for anything important, and the ones I have left will be for shop jigs only.
Those grk screws are the only ones that are allowed to use in structural framing in replacement to nails
Nice to see another vid. Thanks I appreciate the insight.
Thanks for going out and beyond the average test ! Good Video and very informative, keep them coming
Good grade of screws is important
12:00 "Tensile Strength" vs. pulling
"Shear Strength" vs. uuuuuh.... _shearing..._ 😅
"Torsional Strength" vs. twisting
"Flexural Strength" vs. Bending (aka 'stiffness')
Last, but not least:
"Compressive Strength" vs. squishing
I think with the close enough sizes of these screws, the metallurgy will do a lot more than the size of the screw. But the size does have some effect