Joint recommendation?

Question

(Yes, I'm building the ubiquitous farmhouse table. I blame the wife.)

What sort of joint would y'all recommend for this?

These are 4x4s. The angled piece is about 36" long on each side, so about 46 before the mitered cuts on the end.

I've used M&T just about everywhere else, but that's going to be a little difficult with the angles. I'm suspect that a butt join would separate at the top over time (though I could be wrong). Someone suggested dowels.

Suggestions?

I'd recommend M&T. what is more difficult with the angles? the tenons don't have to be any precise angle as long as they are exactly the same complementary angles. The mortises can be angled, but not necessarily. — aaron, Aug 01 '17 at 17:18
@aaron The difficulties with the angle are getting the mortises positioned properly, and cutting the angled tenon. I could make a router jig for the tenons, but getting the mortises positioned correctly might require some magic that's not currently in my bag of tricks. There's probably a simple way to address that problem, but my imagination is failing me at the moment. Might be better off doing the tenons by hand. I just know that the shoulders are going to wind up being a few degrees off and leaving a terrible gap on one or both ends. — 3Dave, Aug 01 '17 at 19:06
Dowelling is what I would have recommended if you didn't want to use M&T joints. In this context I don't think you gain any benefit from going with a proper mortise and tenon because the diagonal supports are nearly decorative (possibly even completely decorative), they add a little stiffness/stability but actually the rest of the table should be perfectly capable of standing up to use, and abuse, without any diagonal bracing at all. Another option if the diagonal pieces are not already cut to length is to use halving joints, what you might know as half-laps. — Graphus, Aug 01 '17 at 19:35
@Graphus They're not yet cut. Well, they've been cut, but about 2' longer than necessary. I tend to work one end of the piece before cutting the board to length, in case I have to cut off the tenon or whatever and re-do it. Half lap at an angle might be interesting. I'll sketch it up and see how it looks. Thanks as always. — 3Dave, Aug 01 '17 at 19:37
One of the advantages of half-laps is the minimal amount of marking out. You can form the projecting 'tabs' on the diagonals and then use them to directly mark onto the stretchers, no laying out from scratch there at all. But I wouldn't bother here TBH, dowelling would be so much faster and more than strong enough for the application.... come to that, butt joints would probably be adequate! — Graphus, Aug 01 '17 at 19:41
@Graphus Cool. Now I just need to figure out how to mark the dowels (Google is my friend, guessing brads). I could just clamp the piece in place, drill through it and have the dowels go all the way through the (predominantly decorative) brace into the stretcher. Guaranteed to line up correctly, easy to do. Hmmm. It occurred to me that flipping the braces so that they were close at the top and far at the bottom would be more structurally sound, but, with 4x4s and a 2"-thick top, I doubt this thing is going to move much. — 3Dave, Aug 01 '17 at 19:45
@DavidLively - regardingt he M&T - doing these by hand (or at least the marking and cleaning up) would absolutely be the most minimally complicated way of assuring the joints are where they are supposed to be. If you go the dowel route, I'd definitely vote for through-dowels for just that reason. I would not do a half lap here - it's easier to excavate waste than a mortise, but you're all show surface, so the joint has to be fit absolutely perfectly. — aaron, Aug 02 '17 at 11:52
If the rest of the table is already joined, I am not sure if you would be able to fit the tenons into the mortise slots. What I mean is, the rest of the table would get in the way. If you stick the first tenon in the top left portion, you would not be able to get the other tenon in the bottom portion because now the bottom tenon is running into the bottom rail. Unless I am misunderstanding something. — jbord39, Aug 06 '17 at 17:10
@jbord39 no, it's not glued yet. I think I'm going to go with dowels. — 3Dave, Aug 06 '17 at 17:11

3Dave · Accepted Answer · 2018-05-11T19:35:22.533

6

As usual, I received a lot of great advice in the comments. However, this is SE (in James Earl Jones' voice), so this needs an answer.

(drum roll)

I went with dowels, as can be seen in the pictures below.

Instead of futzing about with making a jig, etc., I clamped the braces in place, and drilled through them into the stretchers. After drilling each hole, I inserted a 4-6" piece of dowel - enough so that I had about 1" protruding on each side of the joint, then drilled the next hole, insert a dowel, next hole.

The net effect is that, though the holes may not be perfectly straight or centered, the joints will still line up. (Mark adjoining faces so that you don't wind up putting the not-exactly-identical pieces in the wrong position or orientation.)

I cut the dowels from a 1/2" rod from Big Box (team Orange). It's not perfect, but it held well enough that I had to disassemble the entire thing, and get creative with gripping tools, to get it apart to apply glue. And, having moved this thing around several times since then, I don't really see the benefit in buying "dowel joiners" instead of a dowel rod, and cutting it on the miter saw. (Though some dowels have flutes for glue passage, which may hold better over time.)

(TL;DR: Put the board where it needs to go, drill through it into the adjacent board, and tap the dowel into place with your mallet. Yes, Mallet. Hammers have their place, but this isn't it.)

I like pictures, so:

Clamped and roped while gluing the dowels: (I didn't have enough clamps, or any 8' long, so I got creative with some rope :) that I found in the garage.)

Truss is nice and stable. I would've liked to have two dowels at each joint rather than one, but this worked out pretty well, as long as no one tries to twist the truss while the table is in pieces.

Need to pick another board for the top from my stack, maybe fill in a few knots with epoxy or something.

Thanks, everyone (@Graphus) for your help. It's been a great learning experience.

Update

We've been using the table for several months; still haven't got around to gluing the top together! But, I'd argue that if you're three year-old can dance on top of it, and the thing doesn't move, it's probably okay.

(Yes, I'll glue it later.)

As it sits:

This wouldn't have been possible without the help I received here. Thanks!

edited May 11 '18 at 19:35

answered Aug 09 '17 at 01:56

3Dave

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Bravo on the follow-through David. And your table is looking great. Extra kudos for using the rope windlass-style for clamping, that's great to see :-) I actually don't know any leisure woodworkers with 9' long clamps (or the budget to buy any!) so this is one of the few ways of actually achieving it and it's certainly the simplest and fastest. – Graphus Aug 09 '17 at 07:19
@Graphus Thanks! The table isn't perfect, but I'm pretty happy with it overall. Still looking at different ways to join the top. I wasn't sure what the windlass-thing was called, but it seemed like a logical way to go. – 3Dave Aug 09 '17 at 17:08
Few things made from wood are anything close to perfect, even professionally made stuff can be full of flaws if you look closely enough! Anyway it's said that hiding mistakes is part of what woodworking is all about :-) Re. the windlass thing, you can call it a rope tourniquet but the oldest name for it that I know from old books is the "Spanish windlass". In British woodworking circles it's still commonly called that. – Graphus Aug 10 '17 at 04:13
Oh about joining the tabletop, do you mean into a single panel? – Graphus Aug 10 '17 at 04:18
@Graphus yes. It doesn't need to look like a monolithic slab or anything. Pin thinking with more dowels or biscuits. (I made it this far without screws...) – 3Dave Aug 10 '17 at 04:42
If you are glueing up into a single panel anyway then dowels and biscuits mainly act as alignment aids. That's not to say don't use them but the long-grain butt joint does nearly all of the holding once the glue dries, as long as your joint faces were good and enough clamp pressure is used. – Graphus Aug 10 '17 at 07:32
@Graphus After trying to make a dowel jig a few times and realizing that my drill press is way too wobbly, I picked up a jig from Woodcraft here in town. Works great, and the alignment is good enough that I now only have to sand the top, rather than planing 1/16" off in the middle due to some bowing in the boards. And I can move the ~280 lb table top in pieces and glue it up at its final resting place. :) – 3Dave Aug 20 '17 at 21:53
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Dowelling jigs are da bomb. It's possible to make your own but they're cheap enough (in contrast to some pocket-screw jigs!) that they're well worth buying. 280lb tabletop! That thing ain't going anywhere 0_0 – Graphus Aug 21 '17 at 07:07

Joint recommendation?

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