How to fix old chair with worn mortise and tenon joints?

Question

My sisters has the old, possibly antique, chair with mortise and tenon joints pinned my finish nails. The glue failed many years ago and the chair is being held together by the pins. The whole chair racks forward and back by about a foot (like a recliner) apparently because the mortise and tenon joints are severely worn from years of use with broken glue joints. How can I fix this? The first thing that comes to mind is filling the mortise with epoxy and clamping the chair back together. Will that hold? The idea is to fill the empty space in the joints worn with epoxy.

Thanks, Scott

bridger · Accepted Answer

this can be a viable last ditch repair. note that the chair will notbe repairable again. if there is as much slop in the jointery as it sounds like, you willlikely have to add some fiber to the epoxy

Charlie Self · Answer

Someone makes a fiber that wraps the end of the tenon before it is reglued. I think that works with regular glues, so a search might be in order.

He might start with this series:

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he can just Google on "chair repair" including the quotes and pick and choose what is needed.

Charlie Self "Don't let yesterday use up too much of today." Will Rogers

Anne Watson · Answer

If you can get the chair apart,  cover the tenon with pieces of veneer orthe iron on tape they use for edging plywood, and use a hot iron to stickthem down.

Chris Melanson · Answer

Please do not even try using iron on tape it is a disaster waiting to are many other ways of building the material back up that willnot seal the wood the glue used for edge tape  will seal the pours of thewood and not allow wood glue to bind to each other. The edge tape glue hasvery little holding power or shear strength.    There are many other ways of building the material back upIE: cutting the existing tennon down 1/16 on all sides making a new mortiseto go over the tennon and then resizing to fit the old mortise aftercleaning it up and re squaring it.

Lazarus Long · Answer

Some of the problem here seems to be that the mortises are probably no longer straight sided. The racking has been working on an edge or face to make it angle away from the bottom. Same with the tenon. Given the now odd shape, perhaps cutting the mortise slightly larger, filling it in with a block of wood, then going back and recutting the mortise would fix that, Just about same thing with the tenon. Carefully check that all four faces are perpendicular to the shoulder. If not, make them so and then add veneer as needed. The new mortise should be sized to the now fixed tenon.

It's a lot of work.

How to fix old chair with worn mortise and tenon joints?

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