Chair repair advice?

[Victorthesecond]

Good morning all, and Happy New Year! I wonder if you might have some good advice for an enthusiastic amateur? Over the holidays, we managed to break one of our dining chairs. (It could have been a lot worse, happily the occupant at the time went down very gracefully!). I've attached a few pictures of the damage but basically, you'll see that the entire back (consists of the back legs and rear upright) has snapped at both joints where the seat is attached. The chairs are, to be fair, quite old, But, they are G-Plan, so were a decent buy when we got them. It looks to me that, when they were made, the back was attached to the seat by simply inserting wood into a slot on both side pieces (of the back) and glueing it into 2 other slots on the seat. That in addition to the long slots that run along the seat and also attach to the back. So, I'm thinking I can just chisel out the broken wood to re-create the slots, insert a new piece of wood into each of the 4 slots (ie 2 on the chair seat and one on each leg) and rejoin the whole thing with lots of Gorilla Wood Glue.

Would you agree? If so, is there any tool you might suggest rather than a simple chisel? Maybe a hole saw (I've no idea if that's the right suggestion!) Or, should I simply drill out as much of the old wood as I can and chisel out the rest?

Any other ideas welcome as well.

And, thank you all in advance!

Mike

 

[profchris]

That's a mortice and tenon joint. Your plan is to make what is known as a loose tenon, cutting a new mortice (hole) in the seat sides. It should work.

However, you do need a pretty precise fit, otherwise the joint will be loose and will fail quite soon. From what you write, it sounds as if you're not experienced in that kind of precision - if you have a friend with an electric router who can cut these precisely for you, that would be ideal. If not, I'd drill out inside the mortice outlines and then clean up with a chisel.

Wood glue (Gorilla or otherwise) won't fill gaps successfully. So if you get a close, but not precise, fit, epoxy would be a better choice.

 

[Victorthesecond]

That's a mortice and tenon joint. Your plan is to make what is known as a loose tenon, cutting a new mortice (hole) in the seat sides. It should work.

However, you do need a pretty precise fit, otherwise the joint will be loose and will fail quite soon. From what you write, it sounds as if you're not experienced in that kind of precision - if you have a friend with an electric router who can cut these precisely for you, that would be ideal. If not, I'd drill out inside the mortice outlines and then clean up with a chisel.

Wood glue (Gorilla or otherwise) won't fill gaps successfully. So if you get a close, but not precise, fit, epoxy would be a better choice.

Thank you. Yes, I agree - I am definitely lacking in experience but slowly learning to make basic things from wood. (So far, a bench, a table for a pizza oven, some shelves for my son, a vegetable patch frame - all very basic, but I learn each time I do things!) I think I'll try the "drill and chisel" option and thank you for the suggestion about using epoxy - something else I've learned! Ultimately, we have 5 other chairs, all of which are over 30 years old so I think my wife is planning on using this as a reason to upgrade our dining furniture. This repair may just save me a few quid......!

 

[Victorthesecond]

Thank you. Yes, I agree - I am definitely lacking in experience but slowly learning to make basic things from wood. (So far, a bench, a table for a pizza oven, some shelves for my son, a vegetable patch frame - all very basic, but I learn each time I do things!) I think I'll try the "drill and chisel" option and thank you for the suggestion about using epoxy - something else I've learned! Ultimately, we have 5 other chairs, all of which are over 30 years old so I think my wife is planning on using this as a reason to upgrade our dining furniture. This repair may just save me a few quid......!

Just another thought.....I do actually have a hand-held router (Black & Decker BD66 plunge router) that a friend leant me to play with before making a decision to actually buy one. I've never actually used it yet....But, I could practice on spare wood before attacking the broken chair. I wonder if you might advise on the best router bit to use to strip out the old tenons? Is there a recommended depth for the mortise?

 

[Agent_zed]

If I were you i'd avoid trying to plunge route into the end grain, it could be pretty dangerous for you and the workpiece, unless you were to make a pretty secure jig to hold it all. If it were me I'd cut the end flush on the cross piece and then make a simple L shaped jig to be able to drill into the cross piece in a straight line. (You could freehand drill if you were really careful) If you drilled a series of small holes you could then use a forstner bit to cut out most of the waste wood. You could use a normal drill bit but a forstner bit has the advantage of being able to overlap the drill holes. Then just chisel out the rest to fit a loose tenon as above.

 

[Tris]

Do the side rails splay out or are they parallel? With those grooves it doesn't look like you've got much room for error and if you have to drill a skewed hole to line up with the mortice on the chair back I'd be worried about breaking through the inner side.

 

[Victorthesecond]

Do the side rails splay out or are they parallel? With those grooves it doesn't look like you've got much room for error and if you have to drill a skewed hole to line up with the mortice on the chair back I'd be worried about breaking through the inner side.

Hi, the side rails are parallel, thankfully. I'm thinking that I can use a drill block to carefully drill small holes into the mortice once I've removed the broken wood and made it all flush. I'm a bit uncertain how deep the mortice is at the moment and whether or not it will become obvious as I start to remove the "old" tenon. Any thoughts on what sort of depth of mortice I should be aiming for?

 

[Richard C-D]

The way I've done these type of repairs is to clamp 18mm strips on both sides of the rail so that they are flush with the underside of the rail and extending 10 to 15 cm past the end. You can then rout a slot in the middle of the rail about 12 mm wide (or maybe more to match the mortice ) 25-30 mm deep and extending back along the rail. With a hand saw cut at 45 degrees at the end of the rail up to the point where the tenon starts and chisel this to match the width of the groove. Then prepare a hardwood (beech is best) insert to fit the groove and extend it to make the tenon. This piece will have to be made so it is a tight fit and the shape has to have the 45 degree flair to fit the angle at the rail end. Glue (PVA) and clamp these into the rails allow 24 hours for the glue to set. Clean out the mortices. Do a dry run to check everything fits and lines up. Brush an even layer of glue on the the tenons and mortices , fit and clamp.
Trying to drill into the end of the rail is doomed to go wrong unless you make a guide block.
You said the side rails are parrell although they usually splay a few degrees. If they splay the repair takes on a whole more complications.
These repairs aren't easy and I've seen many failed attempts.

 

[Victorthesecond]

Thank you for all the replies, it's much appreciated that you all take the time to do this. As you have gathered, I'm not a skilled joiner so without wanting to "just take the easy way out", some of the suggestions are a little beyond my capabilities! Last night, I had advice from someone else (not via this forum) who has suggested I 1) cut back the protruding wood (as already suggested in this thread) 2) fill the other mortice with an epoxy liquid wood filler 3) ensure each side is flush 4) fit 2 or 3 dowels with around 3/4" in each "joint" to repair the chair. So, that just means drilling into a solid foundation for the holes required.

Arguably, I could even then put a long countersunk screw in at each side (ie from the reverse of the chair into the new joint) to secure things, and use filler to hide the screw head then paint to become invisible (ish).

I know, this isn't a purist result! But, it might work? Ultimately, it's a spare chair from a set of 6 that we use infrequently....

 

[Victorthesecond]

Just a quick update. My apologies to Tris....a closer look and I see that the legs are indeed splayed to the side rails. So, that does, as you say, make it tricky to drill the hole necessary for either a loose tenon or dowelling and leaves little room for error or strength. We've also found that one of the remaining chairs looks to be going the same way (on it's last legs, you might say..) so are natually concerned enough to take that out of daily use, at least for the time being. It's possible that I may be able to ease the joint apart and re-glue it all.

 

[Agent_zed]

Another (although crude) option is to do your best at a tenon/dowels but then also add a steel bracket. The wider the better but depends on if you have access to any. I'm guessing sizes as i don't know the rail size but 50mm x 3mm running about 150mm along the rails and across the back would give a large amount of strength.

 

[rogxwhit]

Speaking as a chair maker - the design of your chair is rather challenged and leads to the failed joint suffering more stress in daily use than it can handle. The brutal truth is that the chair is ready for recycling. I wouldn't waste more time on it. Sorry for the bad news :-(.