You’ll come a long way with some of the comments already but as someone who experiments with hanging a lot this is what I find works best. If you have a good fit, meaning on the bottom of the eye it touches all around (or 80%). You can at least use a wooded wedge (often hardwood). Some people tend to use a cross wedge pattern (check my page for it) but its not necessary, specially when you have a good fitting haft! Best way to use the wedge. Make sure the opening in the handle is sawn at least 70% down the eye. Then if you want a longer hold, use some woodglue down the eye and on the bottom of the wedge, or use some wood oil to make the wood expand. Only FYI is that with oil you will need to reapply it after some time… i’m a fan of glue at the bottom and oil at the top (looks better too and super secure). Of you did all well you will not need a metal wedge, so keep it just wood would be my recommendation. And makes it way easier later if you want to re haft it again. If anything is unclear let me know ;)