marc:the wood whisperer is sponsored by powermatic. the gold standard since 1921, and by rockler woodworking and hardware. create with confidence. (lively music) it's been a very interesting 2012 so far. in addition to the challengesof being new parents, nicole and i had to dealwith thewoodwhisperer.com
coming under a major ddos attack. now if you're not familiar with what a ddos attack is, google it and you'll see what kind of crap we've been dealing withfor the past month. at this point we just want to get back to business as usual, and put out some greatwoodworking content. i've got just that for you today.
we've actually got a segment from the wood whisperer guild build that's going on right now. we're building the splittop roubo workbench. one of the main ways thatwe're joining things together of course is a mortise and tenon joint, but you can reinforce a mortise and tenon joint with pegs. you're not just pegging them
if you're doing the drawbored technique and that's what i want to show you today. let's take a look at the bench. i could show you where we did these drawbored joints and then i'll show you how to make them. every mortise and tenonjoint on this workbench receives two pins. the pins go through theleg, through the tenon
and into the leg materialon the other side. i guess if it were just aregular mortise and tenon joint with pin shot through it it wouldn't necessarilybe that much stronger but you might be able to avoidcatastrophic failure later should the glue joint ever fail. you still have those pins in there holding that mortise and tenon together. now what we did differently here
is a variation of that technique. the drawboring technique where those holes are slightly offset between the tenon and the hole that goesthrough the mortise. when you drive the pin through you're actually pulling that tenon further into the mortise. it might be a littlebit difficult to picture
if you've never heard this before. we're gonna jump right into the video. now keep in mind, this is in the middle of a build so the mortises are already cut and we're jumping right into the action. check it out. now we still have a fewthings to do to our legs before we can move on.
namely we need to create the holes for the drawbored pegs. basically the short rail tenon is gonna go into the moritse and the rail will come along like this and to really pull that tenon in we're gonna use the drawboring technique and that involves driving a peg in into an offset hole in the tenon
that just squeezes it in and really provides a nicemechanical tight joint so that even after the glue fails who knows how many years from now even when it does fail, that peg will still be there holding that joint nice and tight. it's great for a workbench. we'll get into the details
of the drawboring technique later because right now all we need to do is drill the holes straight on through. i'm gonna head over to the drill press to make those holes but you could certainly use a hand drill to do this if you want to. now you want to refer to the plan for the exact locations of the holes.
they can move one way or the other but we do have it setup for what we feel is the ideal location. basically it's about an inch and 7/8 between the two holes and you want to drill in two inches deep. this way the peg goes allthe way through the mortise, through the tenon and into the meet behind that mortise
and that's gonna make ita very, very strong joint. we'll just line everything up. make sure we're right where we need to be and now we can drill. now our goal is to transferthe location of these holes very accurately to the cheek of the tenon that lies within. the best way to do thatis to use the drill bit we used to create the holes.
it's a brad-point bit so when we push it all the way in once you bottom out here you can kind of justgive it a little twist, put a little downward pressure and that brad-point is going to put a little pinpoint insidethere on the cheek tenon. we'll see that in a little bit. when i do this at each one of the holes
for both the top and bottom rails. now i can disassemble the dry assembly. now we'll take a look at those tenons. i like to use a pencil todarken up the pin holes. makes them much easier to see. now let's talk about the methodology here. if we were to drill ahole right on this point that we put here and then we drive a peg throughthat joint after the fact,
you would have a peggedmortise and tenon joint. the thing is that doesn't really offer any additional strength. it will stop the joint from falling part years down the line ifthe glue ever fails, but it's not really gonna help to sort of hold everythingtogether nice and tight. that's where the drawboringtechnique comes in. the concept is instead of drilling
right on this point that we've created we're gonna drill a little bit back so that when this peg gets driven through it's gonna go into that holeand bend around the hole and thereby pulling this tenon deeper into the mortise. it makes for an incrediblystrong mechanical joint that really doesn't rely onthe glue for its strength. that's the goal with drawboring.
what we need to do here is take this little point and make another mark about well, it kind of depends on how intense you want to get with this but i like to go about a 16th of an inch closer to the shoulder. that will be the location that we actually do our drilling.
with my small square i'mjust gonna line it up, measure out a 16th and put a little mark there. the same thing on the other one. now before i drill i'm just gonna prop the tenon up on a piece of scrap here and that sort of protectsthe workbench top and then also helps me reduce tear out
when i drill through this thing. now i'm just gonna takethat same drill bit and i'm gonna stay in line with the hole but go back to my new line. it's a 16th of an inch back and i'm gonna have myselfa little starter hole. i can just use my hand drill at this point to drill all the way through at the new hole location.
(drilling) i'm gonna put the tenon into the mortise and show you what we're dealing with here. tilt it back. you should be able to see at the bottom of theseholes that extra material because of the offsetdrilling that we did. when you drive a peg through there it's actually going topush on that material
and force this tenondeeper into the mortise with an incrediblystrong mechanical joint. talking about the pegs you have a couple choices. you can just buy some commercial stock and that's what i have here is a 3/8 inch dowel rod. simply cut it to the length you need and i'll show you a few more details
you'll need to know about how to actually drive it into the hole, but you just cut itinto the various lengths and you're good to go. these dowel rods areavailable in multiple species so if you have a lightcolored wood for your bench you might even consider going with walnut or something. maybe you want an accent color.
keep in mind, even if you use a blondspecies for the bench and a blond species for the dowel rod the end grain soaks in finish differently. as soon as you put a little bit of oil or something on it, you're gonna wind up seeing a little bit of subtle contrast even if it's the same species
so it will look pretty cool. here's another option. this is the easy way to go but here is, i guess you can call it the more fun way to go, and that is to take some scrap strips of stock from the project. i've got a ton of theselaying around the shop now and we're actually goingto make our own pegs.
let me show you how that's done. this little beauty is a dowel plate. essentially it's a brute force method of taking a square piece of stock and driving it through the hole so that when it comes out the other end you have a nice, round peg. the advantage here is you number one, get a perfectly sized peg
that's very predictableeach time you do it. you can also use any species you want. any scrap stock you have in the shop you can make your owndowel stock like this which is pretty darn cool. you need to start with something and i'm gonna use these strips to create the stock thatwe're gonna start with. let's head over to the tablesaw.
i have my fence set to give me a cut that's just a hair over 3/8 of an inch. this is a fairly dangerous cut unless you have the right equipment. this is one of those cases where i highly recommendusing a push stick that's intended for a task like this. my gripper is just perfect for it. it's gonna help me guide this piece
through the cut safely, and prevent any sort of kickback incident from occurring. also notice that i tookthose long strips of scrap and i cut them into justover 10-inch pieces here and that's a nice even number so that when i try to cutmy two-inch pegs out of it i've got a little bit ofextra room to work with. let's start cutting.
i think my preschoolteacher would be furious at what i'm about to try to do. i want to put a squarepeg in a round hole. what i'm gonna do here is actually start withthe half inch size first because if i just remove a little bit of the material at the corners i should have no problem fitting it into the half inch hole
and this will clean off the corners for us making it easier to pass through the 3/8. here's the other thing. you want to position this dowel plate on something very sturdy. i do have my old workbench here just because it's a little bit easier in terms of the height but you can certainly use your slabs
on your new workbench to this. just center it over one of the dog holes and grab a hammer and drive it through. (tapping) okay and you can see it just kind of tampers the corners. one alternative method you could do is leave your pieces longer and take a block plane
and sort of pre-clean off these corners if you really wanted to, but sometimes you just usea little extra force here and you get the job donea little bit quicker. all right, this is still not small enough to fit into the 3/8 hole so i'm just gonna keepcutting some material away and bring this to a littlebit more of a finer point. i'm really only focusing on the bottom
quarter inch or so of this peg. that should be good enough. i just want to get it started in the hole and hammer it on through. this will take a little bit of pressure because it is removing a lot of materials. maybe put on some ear protection. here you go. now if you find that yourpeg material is breaking
or crushing under the pressure you may have no choice but to pre-mill some of these pieces and remove that extra stock. in which case you do wantto keep those pieces longer because it's a lot easier tohit this with a block plane than if you're using one ofthese little teeny-tiny pieces. let me show you how wemight do that real quick. i've just got the peg positioned here
between two dogs and the dogs are below the surface. we don't want to plane into the dogs. i'm just using my block plane. i'm gonna take a bunch of strokes. (scraping) remove a good portion of that corner. turn it a little bit toget to the next corner. all right again.
we should find that it goes through with a little bit less effort this time. there you go. before we actually can drive this peg down into a drawbored hole, we want to make sure that we reduce the diameter of the tip. i'm just using the same side that i was originallyrelieving material from
just to get it through the dowel plate because it probably already has some material removed there. my goal is to just taper the bottom quarter inch or so. maybe a little bit more. if you don't do this you're gonna find the end of your dowel, the end of your peg here
will make contact withthe cheek of the tenon where that offset exists and you're gonna have a problem. it's not gonna want to go through. you just bang it through and something is gonna break. this way we taper it on all sides. when it comes down and it makes contact with that offset tenon,
it will actually slide right by it and force the dowel through. this is pretty essential stuff here. with my pegs all milled up we can start to assemble the joints. you have a decision to make. should you or should you not use glue? frankly it's just gonnabe a personal choice. with a joint like this
the strength of this youdon't really need a glue. you can use glue if you want to and i'm sort of one of those people who likes a belt and suspenders so i'm gonna use glue on mine, but just remember it'snot absolutely essential and if at some point in the future you think you might wantto take this thing apart if you add glue you'regonna have problems,
but if you just use pegs you could always drill those pegs out and disassemble the jointat some point in the future. just a few things to keep in mind. i am going to add a littlebit of glue to my tenon and that's the thing. even though i am gluing it, i'm not adding a lot of glue just a nice thin layer.
i don't really need a whole lot. just a little bit in the mortise and let's get this bad boy together. as you can see this isa really secure joint. when those pins are driven home there's just really no question about it. you don't need any clamping pressure. it pulls everything in. you'll see this gap close up
and now we can just let them dry. the other thing is we can start to move on to the rest of the joints. the great part of this is you can move from one joint to the next and you just don't have to rush. (lively jazz music) once the glue is pretty much dry we can cut off the pegs
using a simple flush trim saw here. as you can see the drawboredmortise and tenon joint is exceptionally strong. good enough for a workbench certainly good enoughfor things like doors, frame parts, just about any other project where you don't necessarily mind seeing those pins being exposedon one side or the other. really is a great technique,
something to explore for the future. let me know what projectsyou incorporate them into. now if you're interestedin joining the guild and getting in on this roubo build we've got a number ofvideos already started. the build is in progress but it's definitely not too late. those videos are alwaysthere for you to jump in and start building.
go to woodwhispererguild.comfor more information. you could sign up right there. thanks for watching.