Thanks Mike,

Most center drills are 60 degree I think? Shame they have a that little drill point on the end (Maybe I could turn that down to continue the 60 degree shape?). Anyway I should be able to pickup a 60 chamfer or engraving tool.

So I think the plan would be.

1. Drill 1mm hole straight through. (Hopefully easy in alu?)
2. Use 60 degree tool to hog out material and form 60 shape.
3. Use a small 90 degree tool widen the 1mm hole entrance
4. Use 4mm rad ballnose to blend the 60 and 90 degree shapes by eye?