What Wood Joint is Strongest? Let's Find Out!

well when you're joining two pieces of wood together you certainly have a lot of options today we're gonna find out which one of those options is the best [Music] okay let's talk about how we're gonna test these joints you see in front of you i've made 16 of the most common woodworking joints in both three-quarter inch pine and three-quarter inch plywood here we have my testing rig which is just an analog bathroom scale with a jack on top of it and then a rigid beam to stop the pieces from going through the roof we'll put our piece in here and slowly increase the jack's height and we'll get a recording on the amount of weight applied down to the bathroom scale below this will let us know exactly what joint is the strongest so without further ado let's go ahead and start breaking joints so first up we have our butt joint which is just two pieces of wood glued together at a right angle the pine does a very respectable job breaking at 120 pounds the plywood doesn't fare very well as it broke only at 37 pounds this is clearly due to a failure of the plywood itself and not the joint next up we have a rabbit joint which is basically a butt joint with a shoulder carved out of one side this gets glue and clamped overnight to dry the pine does a very respectable job at 138 pounds you can see a failure of the wood and not the glue next the plywood does a similar job at 129 pounds again we can see a failure of the wood and not the glue next up we have our tongue and groove style joint which is created at the router table using a 3 8 inch bit as this is three quarter inch thick material with the joints fitting nicely together everything gets glued and clamped overnight to dry and the pine does a great job breaking at 205 pounds as you can see the groove weakened the back side there and that's where it broke and then onto the plywood which breaks at 125 pounds this lesser value must be because of layers of plywood and the way this groove is cut next up we have our two inch screw joint which is just pre-drilled holes two inch screws and some glue in between this is far and away my favorite joint to use when building things so let's see how it fares first up is the pine which does an average job breaking at 124 pounds upon completing to break the joint you see it kind of explodes this is likely due because of the wedge shape of the screw pulling its way through and splitting the wood next up we have the plywood which does a little better at 150 pounds its better performance is probably due because of the crisscross grain of the plywood as you can see the brittle screws snap instead of bending like nails next up are pocket screws which over at my homemade pocket hole machine i drilled two holes add glue to the joint put the screws in and let it dry overnight first up is the pine which does a slightly above average breaking at 155 pounds you can see this break is mostly the result of the pocket screws pulling out next onto the plywood which does a slightly worse job breaking at 94 pounds opposite of the pine this failure seems to be more result of the plywood separating next up we have the biscuit joint which using my biscuit jointer i create a slot in one face and one end add a bunch of glue put the biscuit in and let it to dry overnight first up is our pine which eventually breaks at an average of 127 pounds this break completely sheared off the end leaving the biscuit totally intact next up is our plywood which is a slightly worse job at 97 pounds again breaking the board and not the biscuit itself next up is our blind dowel joint i go ahead and use my self-centering doweling jig to drill two holes in each end and then use my centering pins to mark a location in the face these blind holes are then drilled out with a 3 8 brad point bit to make room for the 3 8 inch dowels then everything is simply glued and left overnight to dry first up for the blind dowel the pine which does a respectable job at 118 pounds you can see the piece of wood drilled into the end grain failed splitting the wood instead of the dowels next up the three quarter inch plywood which does a much better job breaking at 148 pounds you can see this break is not a result of the wood failing but again the layers of plywood separating next up is our through dowel the way to make this joint is to lock everything in place using your 3 8 brad point bit drill all the way through both pieces deep into it insert your dowel glue it in place and let it dry overnight once everything's dry i come back with my flush trim saw and then use my sander to make everything nice and flush first up the pine through dell does a slightly above average breaking at 148 pounds you can see this break unlike the blind owl was a result of the dowels breaking and not the wood next on to the three quarter inch plywood which does a great job breaking at 174 pounds this outperformed the blind dowel as the layers of plywood weren't able to separate and this resulted in breaking of the dowel and not the wood next up we have our very basic miter joint which is just two 45s cut and glued together i glued up a pair to make it easier using my band clamp first up we have the pine miter joint which goes all the way around once nearly pegging the scale to its end at 346 pounds very impressive next on to the three-quarter inch plywood which also does an impressive job at 235 pounds surprisingly both miter joints experienced very low amounts of damage to the wood when broken next up we have our spline joint this is created by first creating a miter joint and then cutting out quarter inch slots in the corner and then reinforcing it with some quarter inch hardwood i slathered the joint in wood glue making sure there's a hundred percent coverage then insert my quarter inch maple piece once that's dry bring it over to the bandsaw cut off the excess and sand everything flush first up we have the pine spline joint which is really fun to say but maxes out my scale quickly and breaks at an astonishing 400 plus pounds very impressive it appears in this break that none of the pine broke but the maple instead next up is the three quarter inch plywood spline joint which also pegs out my scale at 400 plus pounds very impressive again this failure seems to be mostly related to the maple breaking and not the plywood next up is the dovetail spline which again starts with a miter joint and then i use a dovetail bit at the router table to cut those slots then i cut out matching shapes on the table saw cut them to size and slide them in as if they're just regular splines after the glue is dry they're cut flush and everything's sanded smooth first up is our pine which does an amazing job at 293 pounds and the break looks like it's the result of the splines coming apart and not the wood breaking next up the three quarter inch plywood also does a respectable job at 264 pounds this once again broke at the dovetails and not the wood next up we have the loose tenon joint which i create using my homemade domino machine if you'd like to create one of these yourself i have a video and a free set of plans available on my website diybuilds.ca glue is then added to the slots and dominoes inserted and left in the clamps overnight to dry first up for the loose tenon is the pine joint which does a great job at 253 pounds very similar to the break in the blind dowel you can see that the wood failed along the end grain as opposed to the joint itself next up for the loose tenon the three quarter inch plywood does a slightly worse job breaking at 217 pounds this time the break seems to be a result of the layers of plywood separating next up we have our blind mortise which i go ahead and use my cnc machine to cut the mortise and tenon as i'm very lazy and i built the cnc machine so i get to use it whenever i want first up for the blind mortise the pine does a very average job breaking at 152 pounds this break seems to be a result of the mortise weakening the end of the wood and just bulging out the end next onto the three-quarter inch plywood which does a slightly worse job breaking in 122 pounds again it appears that the mortise has weakened the end of the joint and blew out the end next up we have our through mortise which is the same as a blind mortise except the tenon goes all the way through to the other side again using my cnc to make this as i don't feel like doing it myself first up for the through mortise we have our pine which breaks at a respectable 143 pounds very similar to the blind mortise next for the through mortise is our plywood which breaks at 117 pounds for this break you can see the tenon broke off instead of the end blowing out and this is a result of the plywood being strong with its crisscross grain pattern next up is the dovetail joint now i will say this is the first set of dovetails i've ever cut in my life and i think they are just okay though it did help i cheated and used the router to cut out the tails first to cut out the pins i used my router to first clear out the bulk of the material and then came back with a chisel and made everything nice and flush i then slide the joints in glue and let them dry overnight first up is our pine dovetail which breaks at a very impressive score of 267 pounds as you can see this broke fairly evenly and broke on the pins as well as the tails next up is a three quarter inch plywood dovetails which did way worse breaking at 117 pounds as you can see this is again due to the layers of plywood separating and making it much weaker and for our last one we're on to the box joint now i don't have a box joint jig and i don't really feel like setting up anything just for this so again i used my cnc to simply cut these out everything gets glued in place and dried overnight first up for the box joint is the pine which nearly pegs out the scale at 370 pounds just before breaking surprisingly this break was fairly undestructive and most of the wood is intact next onto the plywood box joints which does a slightly above average breaking at 208 pounds this time this break was very destructive and for some reason the outer veneer got stuck and it it's quite a unique break i'll say that and that's the end of the testing as we look at this chart it's easy to tell that the spline was the overall winner of this but very close we had our miter joint which once again blows me away just how strong just a simple 45 is as well as our box joint notable contenders were also the pine dovetail the dovetail spline and the loose tenon well there it is guys we have our clear winner the spline overall blew away this competition now if you guys enjoyed this video do me a favor hit that like button and be sure to subscribe because this was quite an undertaking to do all this so i really hope you enjoyed it and we'll see on the next one [Music] you

Channel: DIY Builds

Views: 29,534

Keywords: Do It Yourself Builds, DIY Builds, Build, DIY, Builds, Woodworking, how to, wood, working, make, create, custom, simple, easy, basic, best, lumber, pine, oak, stain, spray, varnish, poly, brush, nail, screw, quick, cheap, JOINERY, JOINT, WOOD JOINT, STRUCTURAL, INTEGRITY, INTEGRETY, STRONG, STRENGTH, HOLD UP, TOUGH, STRONGEST, TEST, TESTING, SCALE, WEIGHT, MAPLE, PLYWOOD, POCKET HOLE, BRAD NAIL, SCREW, BALTIC BIRCH, plywood, glue, wood glue, carpenter glue, tightbond, lepage

Id: OWFyBCkwLOQ

Length: 11min 23sec (683 seconds)

Published: Sat Sep 03 2022