french corner braces, used on chairs



Hi, following a resent post on this subject, I enclose a diagram of the construction method used; I think it possibly some might have unread the first post.

The early method used was this? One brace is placed at the corner of each leg joint; to equalize the strain generated by the seat webbing, let me explain further? Lets take the front rail, leg, and the connecting side rail, as a example, a brace, say 5" long x 1"x1", this is placed equally across the corner, then marked with a pencil line, a housing joint is then made 1/4" deep in to the front rail & side rail.
The chair is then glued up.
After cleaning of the excess glue from all the joints, the proposed brace is placed over the pre-cut housing joints and marked and cut to the corresponding housing joint, (I like to wedge this cut on brace) this is then just glued in place. When dry, and the webbing are stretched to the desired tension.
This Conclusion can now be made. No pressure is on the leg mortise & tenon? But on each rail housing only, the front pressure is transferred through to the side rail, and visa versa. So no other fixing (screw or nail) is required, just a good tight fit, and glue.

I was taught a variation of the brace shown that is somewhat more complex,  but provides additional support.

The center one third brace is extended into the side rail by a triangular ( in plan form)  tenon cut  in the part of the brace stock that is removed in your version and is inserted in a matching triangular mortise in the rail.  This tenon may also be pinned with a dowel for added security.

Hi Karl, both are similar ways, though I have never seen your version used in England, am I correct in thinking your will have to fitted your version when the chair is first glued up. (Thus: making it more complicated) as the method I show is fitted after gluing up, (then just taped home) as my version is held by compression (web tension/strain) and the full depth of the brace (1") is carrying, against your 3/8" in your version, It is convincing me that the way I was taught holds more fruits, as the corner block is more easily replaced when repairs are carried out, marking and cutting, carried out with the frame in situe.
Could you show us all a diagram of your version, and then a comparison of the two methods could be made.

May be important to mention this brace is not found on Philadelphia "Chippendale" chairs.  Corner blocks are typically built up of two pieces of 4/4 and glued parallel to the leg.  After they glue dried they gouged or sawed the blocks into a quarter round shape.  Never seen diagonal braces on a Philadelphia chair.  That's not to say there aren't some.

I believe I was the one who was first talking about this. I ended up using the method described by Karl. This made the chair extremly ridgid. But the chair was already ridgid from the mortise construction.

If I ever make another chair like this I will probably use either the method Joe or Adam recommends. Since although the corner braces added rigidity, I think it was over kill and didn't do anything the block styles wouldn't.

And took alot of time!
I picked up this French brace, method as an apprentice, around, 1959,while working at "Taylor & Hobson Ltd".
I had a large batch of Chippendale "Rococo” chairs to repair, leg’s & rail’s needed renewing and repairing.
I was informed they were to start a collection by "English Heritage". (So needed my best work).
This was the method used by them, (all Possibly made in the mid-late 1700s).
Taylor & Hobson carried out the full restoration.
This design, Is a strong, quickly made, yet light method, needs no other form of fixing but a good tight fit, and glue, cannot become lose, while under strain from the webbing, which holds them in place.
I suspect this would have derived in France, in Louie XV day, but theirs was gesso and gilded, with applied moldings, Chippendale changed their method to solid wood, plus a little skill? Of coarse.