Thanks.
Here is the tools that I used to slit and drift this hatchet. Top center is the slitter on a bent handle so I could hold it easier under the power hammer dies. To the right is the next drift that spreads and lengthens the hole and then the final drift on the left.
This is the slitter showing the angle. This is probably mild steel (I don't remember)so I have to reshape the end from time to time.
That picture also shows the orientation to the power hammer dies. I sometimes turn things lengthwise depending on the need.
This is the final drift. It is driven in top and bottom of the head to impart an hourglass shape to the hole. After this, if I need more flare to the eye, I will hang the rim of the eye on the horn tip and tap it lightly working it around to get it even.