because of nails in all of the joints. Nails do nothing to increase the strength of the chair, but do weaken the wood where the nails were used. This chair belongs to a friend, it was ‘unfinished’ furniture, table and chairs in oak. Why the original manufacturer used nails is beyond my comprehension.
Not being able to disassemble the chair to deal with the break or perhaps replacing it, it was necessary to repair in place. I clamped the stretcher then cut a small mortise across the break to receive a loose tenon to strengthen the fracture.
The depth of the mortise is to the end of the cross stretcher. This is an inherently weak joint, exacerbated by the through nail weakening the joint even further. The above picture shows the break spread open to receive hot hide glue.
I used 192 gram strength ground hide glue from Joel at Tools for Working Wood, high quality ground hide glue; 1/2 teaspoon glue, 1 teaspoon distilled water. This is the smallest batch I make, put it in the glue pot, the pot on the stove and when the water jacket boils over, the glue is ready in minutes.
I used a tourniquet and a couple of wood end cam clamps as well as a wedge of pine between the front legs to close up the fracture, not the easiest clamping job, but I accomplished the task.
Using a flat chisel I pared the excess oak away to bring the tenon down to the curve of the stretcher. Then some shellac with yellow ocher and burnt umber to get the color match and a bit of beaumontage to optically hide the fracture and joint around the loose tenon.
Cursing the inappropriate use of nails.