Help With Failed Table Joinery

[Jason Hanko]

Hey everyone,

Well the good news is that I finally finished the trestle table I was building, and it looks great! The bad news is, after about 6 months the joinery that holds the stretcher has failed.

The table is the Trestle Table from Woodsmith Vol 31 No 181. The Stretcher is notched to create a waist, which is trapped between two notches in the legs (see pics below). The joints held fine until recently, when I noticed that the tables is a bit more wobbly/rack-y. (My 6 and 4 year olds treating it like a jungle-gym may have contributed to this, but they deny any responsibility... )

It is not possible to remove the stretcher from between the legs at this point and re-glue the joint, as the legs are now trapped int he arms/feet of the table. As you've probably deduced, I'm looking for a way to shore up the joint again. Im not convinced that just injecting glue into the joint will do the job. I've though of drilling into the stretcher/leg somehow to join them together more securely, but Im not sure which angle would work best from both a structural and aesthetic point of view.

Any tips or other ideas would be greatly appreciated. Thanks!!!
2012-06-24 21.23.06 (2).jpgIMG_0013.jpgIMG_0012.jpgIMG_0014.jpg

[Jamie Buxton]

Add two diagonal braces. One end of a brace fastens to the trestle just above the stretcher, and the other end of the brace fastens to the underside of the table top, perhaps ten inches away from the trestle. There is a brace at each trestle. The braces hold the trestle/top joint rigid, and the stretcher becomes a decorative piece.

The brace joinery can be mortise and tenon at both ends. With a router and an edgeguide, you cut the mortise into the trestle. It will be a vertical slot, centered on the existing slot. The mortise on the underside of the table is a slot running the long direction on the top, again cut with a router gudied by a straightedge. You probably have to make the tabletop mortise longer than the mortise so you can do the assembly. The trestle end goes in first, and the tabletop end kinda slides horizontally into place. That the slot is long has no effect on the M&T strength; the glue on the tenon cheeks is what holds the joint together.

[Brad Olson]

That is a cross-grain joint that will never hold as designed, especially with the gap between the legs. Due to the gap, the two halves of the leg can move independently instead of moving together without the gap. Even worse, then can flex away from the tenon, since it isn't a true mortise, allowing it to pull away from the only glue surface on the cheeks. Add a few kids having fun under the table and this is a joint waiting to fail.

Ideally that would be wedged or pegged on the outside. If you keep glue off the wedge, you can just give it a tap to tighten it back up again. Stylistically, I would add a vertical wedge, but there are many options.

[Scott T Smith]

Here is something to consider. Add butterflies to the legs above and below the stretcher. The objective is to keep the legs from moving further apart. Then, convert the ends of the stretcher into a wedged tenon, tightening it against the legs.

[Jerry Wright]

Good solutions offered. As to cause, you need to look no further than the Diag in Ann Arbor and its vindictive Wolverines. Go Blue!

[Bill ThompsonNM]

Since you don't have much space for a wedge in the cross brace outside the legs I would cut one on the inside of the legs. You then tighten the joint by tightening it as necessary. Alternatively, you could cut off the ends of the cross piece, take the table apart and make a new cross piece with a bigger hole between the legs and a wedged tenon n the outside. Might even be able use the same crosspiece, you'd just end up with a base 6 inches shorter which might still work fine.

[Thomas Hotchkin]

Jason
Dry winter has dried out legs, stretcher now loose in notched waist. You can make a shim plate to take up seasonal wood movement at stretcher outer shoulder at both ends. Tom

[Stephen Cherry]

I'll take a stab. I would consider cutting off the ends of the stretcher with a flush cut hand saw, taking the table apart, cleaning the failed glue off, and reassemble with with tan 3m 5200. 5200 is super strong, but flexible. In this sort of cross grain situation, it can absorb the normal expansion and contraction.

Then the cut off nubs could be reglued back on with the 5200.

[Jerry Miner]

This joint relies on a tight fit at the stretcher-to-trestle leg connection. Fiber compression through use/stress and/or shrinkage can loosen the fit. Traditional trestle tables like this often have a "tusk tenon" joint---a wedge (the "tusk") is driven into a mortise in the stretcher, and can be driven tighter as needed over time.

Your table lacks this feature, but one way to include it as a retro-fit would be to add a wedge to the inside face of the trestle (it could be done on the outside, but you don't have a lot of extra length on the stretcher there)---something like this:

Trestle 1-13-13.png

I show a peg driven through a hole in the strecther to engage the wedge, but it could be a piece attached to the face instead, or .....

[Jason Hanko]

Hi everyone - thanks for all the great ideas! I did finally end up repairing the joint, going with the wedging idea that Brad and Jerry suggested (extra thanks for the excellent Sketchup Illustration, Jerry!)

To start I drilled a hole for a 1" peg through the stretcher - I used some scrap to make a jig to help keep the hole straight.
2014-03-23 09.49.32.jpg

I put a shallow dado in the peg to both hold the wedge laterally and give them a flat surface to engage.
2014-03-23 09.52.18.jpg

Heres the jig I made to cut the 8° angle safely on the small wedges.
2014-03-22 14.04.44.jpg

Wedges are in, any my table is rock-solid once again!
2014-03-23 09.32.24.jpg2014-03-23 09.33.19.jpg2014-03-23 09.33.02.jpg2014-03-23 09.49.14.jpg

Thanks again everyone for the suggestions!

[Ken Fitzgerald]

Your recovery efforts look like they were part of the original design Jason! Well done Sir!

[Bruce Page]

Excellent recovery!

[Jerry Miner]

Nice recovery, Jason! As Ken said, looks like it was planned that way all along. You should let the guys at Woodsmith know----their table probably has the same disease!

Thanks for sharing the "after" photos.

[Chris Friesen]

Not your fault, but the original design looks flimsy to my eyes. For comparison, on this one (http://d2amilv9vi9flo.cloudfront.net...tle_Table1.pdf) the stretcher is about 7 1/2" high at the ends, giving it more resistance against racking. It's fastened with through-tenons that are both wedged and pegged.

[Steve Rozmiarek]

Not your fault, but the original design looks flimsy to my eyes. For comparison, on this one (http://d2amilv9vi9flo.cloudfront.net...tle_Table1.pdf) the stretcher is about 7 1/2" high at the ends, giving it more resistance against racking. It's fastened with through-tenons that are both wedged and pegged.

I agree, those splits up the legs don't help anything either.