The fiddle has a sizeable heel, which I left on there so I could either screw into it from inside the box or - and this is the current favorite idea - bolt it on.
But since the neck is at an 8 degree angle, how the hell do you drill those holes in the endgrain of the heel, and line them up with the holes in the box? Do I glue it to the box and THEN drill the holes, and if so, how do you get the drill in there? It is a tight squeeze.
The blue tape at the scroll marks where the plated tuners go.
These are the things that keep me up at night.
Taking the box apart would be the best plan, however no go with this box. Rusted in nails ain't goin' nowhere.
I'll look at the 90 degree attachment.
Make a small drill jig to line up with the neck and box. Simple piece of scrap timber will do just fine. Then drill thro' jig from one side for the box and the opposite way for the neck.
Paul H suggested I tip the table on the drill press to be perfectly 90 degrees and clamp the fingerboard surface of the neck to it and then just drill through the whole heel.
I'm inclined to go that route, and run bolts all the way through to the inside of the box. Maybe T nuts, maybe regular nuts. But use fancy brass bolts so they look good from the outside.
Two bolts lined up vertically ought to do it. Plus countersinking so they are recessed.