I have filled many holes to full structural soundness using solid maple plugs and a modern 2 part epoxy glue. I prefer this to dowel for larger holes. First i make the hole round; then I cut the maple plug with a modified hole saw (removed the centre drill bit and substituted a bolt to use as the mount) then shape with a Dremel. The new epoxies can be sanded and drilled and are rock solid. These are the first ones I ever did:[IMG]http://i56.photobucket.com/albums/g179/troutstudio/Rogers/034278ab.jpg[/IMG]
Which 2 part epoxy do you use?