It is easy Nick, this was one of my first "useful" projects.........

And I made it real hard by using the toughest bar of steel I could possibly find. Put it this way, even drilling it was impossible as I showed in another project I used the same bar stock for. But I managed to make a tool holder......

The hardest part is without doubt the dovetails, not making them, but getting the size right. Take too much material off in one pass and it's scrap...start again.
I guess you should really make the dovetail first before anything else just in case.