Hi Nigel,
Yes you will need to drill a hole first but drill it slightly undersize so the tool is a tight fit. For tools with tapered tangs you will probably need to drill a stepped hole using two or three different sized drills.
I usually drill the hole before turning the handle and use that to centre the blank between centres so that way you are guaranteed to have a concentric hole.
When finally inserting the tool into the handle, tap it in to get it started and then hit the back end of the handle with a wooden mallet, the inertia will make the handle start to move into the hole. Keep hitting until the tool is fully seated in the handle.