Broken Dining - Chairs Need Bracing Ideas

[Brian Kent]

These dining chairs are 21 years old and are heavily used. We have houseguests each week who are on the hefty side (260 lbs to over 300 lbs) and play games at the table for 6 hours at a time.

I have repaired them many times, including several rounds of complete disassembly, cleaning out all old glue. Re-gluing, clamping, screwing. But the forces are strong and persistent on these lightly braced joints.

We are ready to add new bracing to the design, even at the risk of problems in stain-matching or having painted metal showing.

So I am open to your ideas on how to improve the design.

I have 4 other photos that are failing to upload, so I will keep on changing formats and see if I can make it work.

[Brian Kent]

Trying to load more photos

[Mike Henderson]

If you took the chairs apart and did some good loose tenons in the side seat rail to back joints, and you glued them with good glue, AND you put good corner blocks inside the seat area, there's not much more you can do. You could add bracing lower on the chair legs, from front to back and one across those braces, and that will help.

But perhaps the best thing would be to make some more robust chairs for your guest. Make them of a wood like pecan (hickory) and make the back and seat side rails beefy so that you can put in a strong mortise and tenon joint between them. That joint that gets the most stress so you have to make sure that area is very strong. The wood choice needs to be something firm and strong, not wood like mahogany that gives too much.

Mike

[Brian Kent]

Sorry. I have tried about 20 times to load photos that would show the underside. Each joint consists of 2 dowels. Then there is a corner brace which had a finger joint on each side. There is one screw through the corner brace to the leg.

[Mike Henderson]

Sorry. I have tried about 20 times to load photos that would show the underside. Each joint consists of 2 dowels. Then there is a corner brace which had a finger joint on each side. There is one screw through the corner brace to the leg.

Take those joints apart and put in a loose tenon. Two dowels in that joint are absolutely not sufficient - they just do not have sufficient glue area to hold.

I've repaired quite a number of chairs. If you put in a good loose tenon, it will hold much better than those dowels. I never (no far) had a chair come back with a loose joint after I put in a loose tenon in that joint. Use epoxy glue to glue them and leave them in clamps overnight.

Glue in the corner blocks and put at least one screw at each end of the corner block. Two screws (top and bottom) on each side of the corner block is better. Use beefy corner blocks.

Commercial chairs like those are often not well made in that joint.

Mike

[Brian Kent]

Mike, for the loose tenon, this looks like a time that the bead-lock tenons would work well. Have you seen any drawbacks to these?

Otherwise, how do you recommend cutting the mortises? I have usually used a Ray Isles chisel or drilled the mortise and chiseled out the waste. Routers are not my friend unless I have really solid jigs, but I have not made a jig for mortises yet.

[lowell holmes]

Mike is correct.

It just happens that I have some experience with dining room chairs. My daughter and her husband have a dining room suit that the chairs broke down at the dowel joints. After several attempts to re-glue the dowels, I bit the bullet and removed the dowels. I made mortises and slip tenons in the joints. After gluing the slip tenons in place, I put 1/4" dowels through the joints perpendicular to the tenons. The only way for them to fail now is if the wood in the chair fails. Brian, I chopped the mortises with chisels. If you take small bites with the chisel, it's not difficult.

It's been awhile since I did the repair and they seem to be holding.

[Mike Henderson]

Mike, for the loose tenon, this looks like a time that the bead-lock tenons would work well. Have you seen any drawbacks to these?

Otherwise, how do you recommend cutting the mortises? I have usually used a Ray Isles chisel or drilled the mortise and chiseled out the waste. Routers are not my friend unless I have really solid jigs, but I have not made a jig for mortises yet.

Unless you already have everything for those bead lock tenons, I'd just hand cut the two mortises.

The way I'd do it is to take the chair seat side and cut a mortise into it then glue a loose tenon into it. Set aside and let the glue set firmly. Then cut the mortise into the rear leg. Trim the mortise or the tenon so that you get a good fit. If you go too far (your fit is too loose), glue veneer to the side of the tenon.

As Lowell suggested, I'd chop the mortises with a chisel, although I might drill out the area a bit first to make it easier. Certainly, you can drill out the dowels if they didn't come out on their own. Depth is up to you but I'd go about 2" in the side rail. You're limited in the back leg so I'd go as far as I could without going all the way through (just for looks). I don't pin the tenons, just because the pin shows. If you want to pin, I'd recommend drilling from the inside and don't drill all the way through. That way you can pin and the pin won't show from the outside. But I believe a good mortise and tenon with good glue is sufficient by itself.

Another approach I've used is to use the Festool Domino to make your mortises. I find that one tenon is not big enough so I make two cuts next to each other to make the mortise wider. Then I cut the sides of two dominoes and glue them together to make a wider domino (tenon).

You live fairly close to me so if you want to bring one chair (or even a couple) over to my house, I'll work on them with you.

Mike

[ron david]

those types of chairs are made to fail.chairs are also the most used piece of furniture in your house. if you are frequently having those people around, I would suggest getting better built chairs. there is not enough strength at that rear joint to sustain large people when they push back on them esp. if they don't lift their backsides when they go to push the chair back to get out of it. chairs with rungs usually help with the stress to the backs of chairs. most all chairs will have to be repaired for looseness in their lifetime.
good fitting joints are always required and glued properly usually makes a good joint
in those chairs a m & t joint will also fail. epoxy is not the answer. epoxy is no better than any other adhesive if the joint is made and executed properly, but turns the item into a throw away in case of failure. I think that epoxy add confidence to people who are unsure of their skills
ron

[Lee Schierer]

I agree with Ron, it is time to get some more robust chairs for your "hefty" friends. The long lever arm of the back, coupled with the small joint area lends itself to failure when heavily loaded.

[glenn bradley]

The repair as Mike suggests is the first phase of a fix for this. The second is to realize that these are "dining" chairs. You sit down, you eat, you get up, you leave. Gaming table or bar chairs are constructed differently and will take the hours of sitting, shifting,leaning, stretching, etc. that goes on around a gaming or cocktail table. Get some of these and break them out for "game night" and be happy.

[Andrew Hughes]

I also say time for new chairs, here's a nice looking chair in the maloof style. I think its mesquite.

[ron david]

The repair as Mike suggests is the first phase of a fix for this. The second is to realize that these are "dining" chairs. You sit down, you eat, you get up, you leave. Gaming table or bar chairs are constructed differently and will take the hours of sitting, shifting,leaning, stretching, etc. that goes on around a gaming or cocktail table. Get some of these and break them out for "game night" and be happy.

there are dining chairs and then there are dining chairs.
ron

[Mike Henderson]

Just a comment on why I recommend epoxy. As Ron commented, if your joint is "perfect" it doesn't much matter what glue you use - any modern glue is stronger than the wood. But when I'm making a recommendation to someone else, I don't know if they can make a "perfect" joint and epoxy has gap filling qualities. PVA, for example, does not have gap filling capability. So epoxy is a "safer" recommendation.

So why do I use epoxy. I think I'm pretty good at cutting mortise and tenon joints but epoxy is "safer" in case I'm not as perfect as I thought I was. And as far as epoxy being a permanent glue, any glue except hide glue is essentially permanent.

Mike

[lowell holmes]

The chairs I worked on are teak and are heirlooms..

It was not a matter of getting new chairs. If that were to happen, it would be make new chairs.