The Haunched and Drawbored Mortise and Tenon
Part II: The Tenon
by Bob Smalser
This article first appeared as a thread on theWoodNet woodworking forum. It was compiled and reproduced here for easier public consumption. All Text and Images are the property of Bob Smalser.
In continuation of Part I: The Mortise.
The tenon cheeks can be cut with the back saw, table saw and tenoning jig, band saw, or crosscut on the table saw using the stack dado set. It doesn't much matter..just insure that you cut to the outside of your scribed lines for a slightly fat fit to be shaved down lightly with the shoulder plane. Why? Well, this especially applies to crosscutting with the dado set, but to a lesser extent applies to many saw cuts. Sawn surfaces aren't perfectly clean.that fuzzy surface is composed of tiny bits of short grain most noticeable in crosscut tenons.and that short grain does not provide the high quality glue bond a cleaner, planed surface does. Yeah, I know, it's a small point with today's modern glues, but it's a point worth remembering because it can still be overdone, especially by neatnicks using the minimum amount of glue to avoid cleaning squeeze out.
When using handsaws, tilting the workpiece away from you and beginning at a corner is the most efficient technique for hitting the outside edge of those lines on the first try.
I whip out the shop-made miter box to cut the shoulders square.
.rip the lower edge of the tenon and the unmitered section of the upper edge.
.and finish the miter using the dovetail saw. The more perfect my layout and saw cuts, the less plane work will be needed.but providing I remain outside those scribed lines, even my sloppiest cuts.and there are certainly some sloppy ones here.can be easily planed to perfection.
The sawn tenon shoulders are brought into perfect alignment and the tenon cheeks and edges are shaved as necessary for snug fit. A feature I like in the Stanley #93 is it is ergonomically designed to be pulled as well as pushed.. because it is easier to keep your planed surface flat and square by alternating the direction of the plane when taking crossgrain shavings.and not having to reposition the work piece makes this technique very fast.
You can see from the relatively small pile of shavings that bringing the tenon from "won't fit" through "drive fit" to "snug, heel-of-the-palm, hand fit" didn't require much work. The edges of the tenon can be relatively loose compared to the tight cheeks, as chopping hard with that steep-beveled chisel has compressed the end grain at the ends of the mortise slightly.and they'll swell back some as the humidity increases.
A technique I use on fine furniture I'm only demonstrating here is to pare the tenon shoulders inward from the edge slightly using a bench chisel. This insures a perfectly tight shoulder-post fit by removing any impediments in the tenon-shoulder corners.
To make the drawbore, I simply point a dowel and drill a plumb hole to match through both mortise cheeks.
.then dry assemble the joint and use an ice pick from my lofting kit to mark the hole center on the tenon.
The joint is disassembled and the hole for the tenon bored a 16th or so inboard of the mark for the cheek holes toward the tenon shoulder.
.and I prepare for final assembly. The post is cut to final length, glue is applied, the joint assembled, and that pointed peg driven through the offset holes.
.which pulls those shoulders with considerable force against the post for a bulletproof structural joint that really needs no glue.
One pin.or two? Depends on how the piece will be used and scantling size, but every additional hole weakens that tenon, and I tend to use two pins in wider tenons than this one of an inch-and-a-quarter width. None of this matters all that much if the joint is well constructed. Most mortise and tenon size schedules for the scantlings I'm using today call for a wider and deeper mortise.but on this piece I want some meat left in the posts in case I want to dado in a side shelf some day.
.and if this work table is ever knocked off of the loft 10 feet to the concrete floor below, it's gonna break at the center of a post or rail before it breaks that joint.
"Can you talk a bit about the pin? Do you try to align the grain of the pin in any particular way? I put some maple pins in a maple table apron and inside my midwestern home they have raised somewhat over the past few years (They protrude a bit - detectable by eye or finger). Also, do you see compression shrinkage showing C shaped gaps on either side of a pin over time? Bruce Hoadley in Understanding Wood suggests a thin kerf down the middle of a pin so that any expansion any contraction occurs there and the pin stays glued to the hole's sides. My questions relate primarily to a finer furniture situation. "
Given the location of where these joints are in a piece..slightly masked by the tabletop..I don't believe the small amount of protrusion is worth any extra trouble. Kerfs sound fine, but all these pins eventually become proud.kerfed or not.with seasonal movement. It's part of the character of the piece and what differentiates a traditional piece from something made in a factory.I don't try to hide any of that.
"What are some good alternatives to the Stanley #93 for fitting the tenon to size? I don't want to spend an arm and a leg plus finding antique planes may be tuff."
I used a worn-out old family low-angle infill for decades before I finally broke down and bought the #93 for 50 bucks a few years ago. You can do the same basic work with a bench chisel.just more slowly and with less precision.
"Is there an advantage to the 45 degree haunch, as compared to a 90 degree haunch (kinda like a shorter section of tenon? "
The mitered haunch is slightly weaker than a square haunch but is much faster and easier to cut and doesn't show at the top of the post like the square haunch does. Both aid in preventing the tenon from twisting during racking force, prolonging the life of the glue joint. Wider tenons are often haunched on both edges.
"What's with all your posting everywhere? Why not just set up your own site? Sharing knowledge is a good thing but yours seem more ego oriented. Does anyone need online courses like this? It's great that you are so efficient with hand tools, but really who cares? If we want a class we'll take one. At least we can pick the topic. "
"Bob, is there some special reason you're not doing this kind of thing for a living, or at least getting paid for it? Your tutorials are great, and I'm very pleased to see them here, but I suspect there are magazines out there that would be glad to fork over some $$ for your stuff. "
No sweat, gents, and thanks for the input. The occasional negative comment only stirs interest and it gets wider exposure, giving me better feedback.
I grew up in the 1950's working for two older generations worth of family members who worked as shipwrights, boat carpenters, masons, carriage makers and home builders...men who I loved dearly.most of whom didn't go past the 8th grade, but made me go to college. These postings are merely chapters of a book I'm doing for my kids and grandkids so the legacy of those older generations won't be lost forever. It's not really much trouble to add the camera to the tool kit during the day and write them up at night instead of watching TV.
I found out a little more than a year ago that teaching myself enuf computerese to post them on the forums provide me superb feedback for clarity revisions, as I've long since forgotten what it's like to begin from a blank page. Thankyou. Commercial sale of these don't really interest me...I've sold a couple...I can make more dough running the sawmill or doing commissions for the extra time and hassle of dealing with editors who take out half the pics and ruin them anyway. Cian Perez, Joe Lyddon and also Ellis Walentine over on Wood Central post them on their sites as permanent articles, so there's no need at all for me to sacrifice any shop time fussing with a website I don't have a clue how to do.
Just keep asking questions so I can figure out how to write them more clearly.
Oh...and having lived overseas up until just a few years ago, I'm also appalled at today's primary "teachers"...the woodworking TV shows. They seem to be either black or white...either all machine oriented, shilling unneeded gizmos.or all museum Neander flavored more for antique tool collectors than the young father of zero experience on a tight budget who wants to make that heirloom cradle for the new baby .no in-betweens like most of us should be ala Frid or Krenov. And the machine shows are so rife with questionable joinery .expensive techniques to prepare and store the next generation's fireplace kindling.and such blatant, crass commercialism, I simply can't believe they get away with it on non-commercial stations. Doesn't firing up that expensive air nailer to drive 5 brads seem patently ridiculous to y'all? When I think harder about that impressionable young father, I can even get a bit roused about it.especially when that 300-dollar production brad nailer does such an inferior job compared to the proper 9-dollar, 6oz Warrington hammer...
...but that's another chapter some day.
"...you will say, 'But where can one have a boat like that built today?' And I will tell you that there are still some honest men who are not scared to use hand tools, who can sharpen a saw, plane, or adze." -L Francis Herreshoff
Return to How-To Index
Return to Woodworking
©2007 Cian Perez / www.CianPerez.com