Mortise and Tenon Joint - Tusk Tenon

hi i'm rob cos and welcome to my shop if you're looking for a really strong joint that includes the flexibility of being able to assemble and disassemble a tusk mortise and tenon joint like i have on my bench really strong i'm going to show you how i do it i'm rob cosman and welcome to my shop we make it our job to help you take your woodworking to the next level if you're new to our channel be sure to subscribe turn on that notification bell and don't forget to turn on the notification on your mobile device so you'll know every time we release a new video good all right back to the bench mortise and tenon has been around as long as furniture has extremely strong joint proven itself over time but there's a nice nice feature where you can make it so that you can take it apart now this is a saw bench that i built so that it would travel in my tool cabinet i needed to be able to put it together have it rock solid i didn't want to use screws and bolts had to be rock solid when it was together yet could be easily could easily be disassembled taken all apart packed into the cabinet and shipped off to the next show so what i did was i used plywood on the ends now the hole in the plywood that we call the mortise and it's not made to be a super precise fit just because of the nature of it the hole that goes through the tenon actually has a slope on one side and that's matched by the wedge so when you tap that in and it's designed to come tight somewhere around the halfway mark tap that in like that that is as solid as you're going to get it and solid as any joint that you would have in that like that now the nice thing about it is when you're done and it's time to take it apart because the slope is slight enough just a few taps from that side it comes apart and there you go i've never had it work loose on me now you'll often see these made with the wedge coming down through the top and to me it just seemed like an awful lot of extra work for no gain you've got a huge mortise to cut as opposed to a much smaller one going through in this case a half inch worth of material and i like i said i don't see any advantage i suppose there could be at some point but these are the ones that i usually do you'll see down the bench same idea coming through the side and i added a little bit of a feature i used a different colored wood just to highlight a little bit i didn't do that on this because the utilitarian nature of it okay this is what i'm gonna walk you through i'm just gonna take it apart so we'll cut our mortise first it's always easier to cut the mortise and fit the tenon to it cut our mortise next thing we'll do is we'll cut the slot through we've got a five degree slope and then the last thing is we'll make our wedge when you put them all together fairly snug you put that wedge on the right side put that in there's no way that's coming apart okay i'm going to use these two pieces of poplar the same thickness which is irrelevant to what we're doing this is going to piece it this piece is going to have the mortise in it which is the square hole this one will be the peg that goes through now you can put a shoulder all the way around i'm only going to put a bit of a shoulder on top and bottom so the mortise is going to be the same width as this piece that's why well if if you want to maintain maximum strength well the any you any amount you cut down the tenon is going to make that the weak link so by just cutting a little shoulder off top and bottom we're maintaining bulk of this so first thing i want to do is i'm going to put it right in the center of this so this measures four and an eighth of an inch so two and a sixteenth is the center and this is 15 16 of an inch wide i'll actually use my marking gauge for that but if we were building a piece of furniture we would obviously have to have this the exact spot we want but for demonstration purposes i'm just going to put it roughly in the middle so this is almost three and a quarter i'm gonna leave about a quarter inch shoulder on either side so our the overall length of the tenon is going to be two and three quarter so we'll come up here two and three quarter and there's lots of ways to cut this i'm going to use a hollow chisel mortiser and i'll show you how i do it but you could chop it entirely by hand with a mortise chisel you could do it with a router but as i said i'm going to do it with my hollow chisel mortiser okay so i've got this this these edges are parallel so i'm going to go ahead and just grab a line from line to line and then flip it over and do the same thing on this side should be right on now why didn't i put my marking gauge here well because the cutter has the bevel on the inside so if i were to do it here i'd have a bevel out here i'd i want the bevel to be on the inside so i marked all the way over flipped it over and did the same thing now i've got to do the same thing actually i don't need to do the same thing on the other side with the hole which is a mortiser i'm going to cut all the way through i don't need to worry about that opposite side so i'm going to go from here to here and i'm going to use a quarter inch hole which is a mortiser so i'm going to come in i'm going to make a quarter inch cut here and i'll do one down here i'll do one here i'll do one here and then i'll do a series of them all along here and along there i'll do one here and one here and that'll take out this piece left off and then i've got to come in here and off i have to clean that up usually the hollow chisel mortise doesn't give doesn't give me a perfect cut now these hollow chisel mortises are pretty inexpensive so if you want to if you're thinking about getting money you want to learn how to use it we recently did a video on you setting it up sharpening it the whole process and we'll leave a link below um so if you'll notice i left the marking gauge line on that hollow chisel doesn't give me a perfect line no matter how careful you are in setting it up you usually have a little less than less than smooth surface but i can go in with a chisel now and just do a little bit of work to that i'm going to go in and define that line that'll give me a nice edge to reference my chisel on i'm going to do the same on the back side now i'll just go ahead with a slight undercut so that i end up with a nice clean a nice clean line on the surface where the tenon is going to interact now i want to define the ends so that they're a nice clean cut marking knife will allow me to set my chisel right down in it now since i'm going to have a shoulder on the inside i'm not going to worry about where the v is in terms of the marking gauge cutter that's too long for my marking gauge but i can use my panel gauge [Music] uh okay so the mortise is done out here on the surface what you're going to see it's a nice clean tight sharp corners everything's nice and straight backside's not bad either a little bit of chip in there but that's all going to be hidden under the shoulders and i've got to remove a little more material in order for it to do that close check both sides in case we take it out of where shouldn't set a square get the sides out of parallel okay and we'll fine-tune this once we've done all of our machining that will give us a chance to get rid of any any marks made in the process so when we're laying this out thing that we have to keep in mind is that we're putting a fair bit of force on this part of the tenon so we need to make sure we have enough material here to counteract that and how much is enough well it's obviously going to depend on the circumstance but i'm going to suggest here we make that is inch and a half three quarter it's yeah two and a quarter inches so we'll go two and a quarter we'll do the same thing on this so i'm gonna set my marking gauge for two and a quarter remember we're only going to do this on the edges and we can come down here just a little bit and we can cut this with a hand saw we can cut with a band saw i'm going to set up the table saw and do it over there so the first thing i'm going to do is i'm going to get this so that my the length of my tenon is correct to this and because i'm centering everything what i'm going to do is just set my table saw to take off i'm just going to take a shallow cut about in here about maybe three quarters of an inch flip it over and do the same thing on the other side and keep moving the fence over until that eventually fits in there and then i'll know where my mark is [Music] okay just a little bit of wiggle room and that's fine now i'll go ahead and set the height of the blade off of that [Applause] [Music] so [Music] you okay now i'm just going to draw a line on here and then take that apart and we'll lay out our mortise that we're going to cut there for the wedge okay so we need to decide how big or how wide we want our mortise to be we don't want to apart well this mortise with our wedge we don't want to sacrifice too much strength so i wouldn't want to come all the way over to here that's probably just about right and it gives us lots of surface area now you have to remember if you're building something out of soft wood that that you run the risk of having that wedge mark up the face of that soft wood so on a piece of softwood you're going to want even more surface area on the wedge harder wood you can get away a little bit less so this is two and three quarter and two inch no inch and a half yeah i'm gonna go with an inch and a half wedge so if this is two and three quarter an inch and three eighths is our half mark what did i say an inch or inch and a half one inch so there's our wedge is going to go now we want to actually go below this line because when we put it together we don't want it to accidentally bottom out so we want a little bit of surface area or a little bit of that mortar sitting below this surface so i'm going to suggest we come in here and use a marking gauge we'll set it so that we're about a thirty second you could even go as much as the sixteenth i'm gonna go about a thirty second an inch below and i'll go ahead and scribe that line do the same thing on this side but we got to carry these lines over uh nice thing about a wheel gauge is you can just roll it to get that last little bit okay i'm going to go over and use the hollow chisel mortiser again i'm going to cut a quarter inch slot out of there so i'll make one cut here one cut here and come back do one in the middle and then take those two little bits then we'll introduce the slope of the chisel okay well our our wedge is going to have about a five degrees not about it's going to have a five degree slope so and we're going to customize the wedge to fit so i think what we'll do is just mark it we can make it as thick as we need i want to make sure that when i come all the way through i get a nice clean line over here because you're going to see that as well so i'm going to make sure that i'm cup about this far and i'm just guessing at this i'm going to take about a about a sixteenth of an inch material off and this is mostly just so i have a nice reference spot for my chisel i'm just going between the lines now chisel's nice and sharp we've got to hold that at five degrees the easiest way to do that is to cut a block i cut a five degree slope on a block and then clamp it right there so that it will hold itself as we chop against it but i don't have a whole lot of material back here so hopefully these two are still no they're not well i'm going to make a new one this is this is out of a piece of soft wood it just doesn't hold as well i'm going to take a piece get a piece of hardwood and go over and cut a 5 degree slope on it if you want this to not move i find lots of applications for this sticky back sandpaper and we'll put that in place put the square on now you know what i don't think we're going to get where we want i don't think that's enough i'm going to move that up a little bit boot there you want it to be you want this to be square to the side so when you put your wedge in and it tightens it's square and not off on an angle you'll see what i mean when we do it now we've got the bulk of it we'll set the chisel right up against the block so all right we got a nice clean you got a backup block on behind you got a nice clean line here and there so when our wedge goes in it'll look nice and crisp now i'm just gonna final step on this just to get rid of the pencil marks just give that a little more freedom to move in there okay so that's sitting below the surface so that's great that'll allow us to pull it in tight and the wedge is going to be an inch but we'll fine tune it and how long do we want to make it well just for looks i'm going to suggest we probably want to go two and a half and then it needs to be well i'm going to start with three quarter and work my way down i'm going to use a piece of osage orange and this is piece i purposely kept it this long just so that i can hold it a little safer on the table saw so we'll take that we'll ignore the two and a half right now we'll take this down to uh to one inch one inch wide and then we'll go over and we'll and we'll draw on there our five degree slope but i want to square up the end too okay i like to have everything squared up just so that when i'm using a surface for a reference i know i can trust it one more okay so we said we're gonna go about two and a half inches so if we came out to here this is more or less just going to be a handle for working with it i'm going to use my protractor and i'll set it for five degrees and we want this end we want this end to come over to about here so if we put that through and put it up tight and just kind of guess at how let's try this again so if we put this through two and a half inches is right there that means we'd have it right about there so if we put that up tight the bottom yeah we're gonna bring that down to about less than an eighth of an inch so we'll start out here at the eighth mark this is what i mean about squaring off the end of the board on the shooting board because now i can set that on there and trust my mark now we're going to need at least 5 16 at the open end in order for it to tighten now we may have to make this a little bit longer or start a little bit heavier there so i'm going to plane that off and give it another go let's try 3 16. there's our two and a half now we said we need five sixteenths to pull it tight which is down here so what we're gonna do is just going to create a bit of a ball up here on the back end which makes it a little easier to pound on and to get a hold of it when it comes time to pulling it out so i'm going to go to the bandsaw i'm going to cut most of this i'm keeping this on because then i'm going to use the table saw to cut that five degree slope accurately [Music] it's not that i can't get accuracy from the bandsaw but it can't get a smooth surface so table saw with a nice sharp blade will give me what i want i'm going to do this in a couple of stages so i'm not having to make that deep cut all at once and to help hold it in place i'll put a clamp on here with a block holding that square now i need something to keep that in line as i do that now i made a mistake and took part of that off i don't know whether i can salvage this or not i'm gonna try i'll move the fence over and see if we can't eliminate that and still use the wedge okay i'm gonna get that to fit before i go ahead and cut the rest of this off okay still have a bit of a problem so when i put that in tight we want to have full contact on the inside but you can see i can move that wedge a little bit so i'm tight here but i'm not tight there now we could just finish it and then do the shaping on the bottom with the on the shooting board but i'm going to go back over to the table saw and i'm going to take another maybe just a quarter of a degree to get that perfect [Music] [Applause] [Music] [Music] do some work on the disc sander so yep okay there's our wedge obviously it goes in from one side now i took a big chunk out in the saw so i'll have to make a new one we put that in place tap that home pulls those shoulders up nice and tight rock solid now i'd go in and cut a little chamfer around here as well you want to leave sharp edges on that okay there you go tusk tenon nice and strong the ultimate in being able to knock something down and put it back together if you enjoy my method of work and like my style of teaching click on any one of these videos to help take your woodworking to the next level i've always said better tools make the job so much easier if you click on the plain and chisel icon below it'll take you to our site and introduce to all the tools that we actually manufacture right here in our shop it'll also give you information on our in-person and online workshops

Channel: RobCosman.com

Views: 44,117

Keywords: mortise and tenon, through mortice and tenon, tusk tenon, wedged mortise and tenon, through mortise and tenon, mortise and tenon by hand, keyed mortise and tenon, wedged through tenon, how to cut wedged mortise and tenon, mortise and tenon joint, How to cut a tusk tenon, tusk tenon by hand, knock down tenon, rob cosman, traditional woodworking, woodworking

Id: CUTRMWzDbQc

Length: 33min 31sec (2011 seconds)

Published: Wed Jul 21 2021