The truss rod was actually routed using a buzzsaw. Which meant the entry and exit left a curve. So using a drill I was able to deepen the slot at both ends.
The glue I used was epoxy. Its my first time using this and it is sticky as all hell. So after making a royal mess I clamped the fretboard and let it sit for 24 hrs to fully harden. Then I had to sand the uneven ends with 35 and 60 grit sandpaper (which sucked) but eventually it became smooth. Then I steel wooled it for smoother handling. Now for fretwork.