How do you repair a maple kitchen table leg that slit in half?

First remove the leg from the table.

Do not sand the leg or tamper with the split at all.

It is best if you can acquire several ratchet straps or C-clamps.

On a table top, lay both halves next to each other. make certain you can put them together and they will seam tightly (dry fit them).

Don't worry about any metal hardeare at this time.

Apply a line of glue zigzagging down one leg (Gorilla glue or regular furniture glue like Elmer's white is best).

Spread the glue evenly over the surface of the leg, leaving about a half inch of dry space completely around the periphery.

Place the dry half onto the wet half, and press together.

Apply your clamps (use blocks or cardboard between clamp jaws and the leg so it isn't dented).

When your clamps are tight, take a wet cloth and wipe away the excess glue that has squeezed out. Let the piece rest for at least 24 hours before removing clamps.

When it is dry, remove the clamps, replace any metal hardware, and reattach the leg to the table. If the leg was originally doweled to the table rather than attached with metal hardware, it might be best to take it to a furniture repair shop.