How do I fix the bottom leg supports of a dining room chair?

Have you tried wood glue? Glue the dowel into the hole and keep tension on it with a bungi cord to make it stay in place until the glue is dry, probably a good 8 hours.

Hello Sew-cazy, hope this video gives you some ideas

https://www.youtube.com/watch?v=xBkce8meWkU

Wood glue is my go to. I usually bind them together as tightly as possible. Bungee cords sound like a good method, although I usually lay it on its side after tying a strip of canvas around it, putting some pressure on it a few minutes. I like Gorilla wood glue.

Please post a picture of the portion of the chair that is broken so that we can see exactly what you have to work with.

Is the hole the stretcher is going into, totally cleaned out? Otherwise the advice given is good, tension while drying and the glue to use. Are you sure the hole is not to big for the stretcher?

If you are doing a replacement dowel, you will need to slightly taper the ends so it fits snugly in the holes, I use Carpenter's glue, tap it in with a rubber mallet, and then use a couple belts to hold firm til it dries.

Yes, be sure the hole is cleaned out where the dowel will go into and the dowel is free of any glue. Put in your choice of wood glue and insert the dowel. From there, you need to create a system of tension to make it stick, you could use bungi cords, belts, something/anything to hold the glued pieces in place. Let it thoroughly dyr and then you should be ready to go.

Best to you.

Use wood glue and put a screw in it.

You need to leave the fix long enough to cure before using it again. Also change around the chairs so the same one is not under so much presure.