I was gifted a beautifully made classical guitar, signed Vincenza de Bonis, made in his shop in Bisignano, Cosenza, Italy, 1953. It's in somewhat rough shape, from numerous old cracks, repaired but reopened(the previous owner & player died many years ago, and I think the guitar has been in a dry climate- southern California- for many years, unhumidified.
The back, sides, and neck shaft are Brazilian rosewood. The neck and heel are glued up, and the joint has separated. As I ponder that particular repair, I'm wondering about the neck joint: I can tell it's not a Spanish heel, because the neck block is a semi-circular piece of softwood(spruce?), with the grain going from top to back. Can anyone say, what type of joint this might be? Did Italian makers of that era, use something in particular: perhaps a dovetail or shallow mortise & tenon? This instrument is very finely made(just an example: the headstock is joined to the neckshaft with a v-joint).
To clarify: the glue joint in the neck heel has separated, not the heel joint to the body.
Hard to believe a handmade European classical guitar from that era wouldn't have a Spanish slipper-foot. The only thing I can think of is maybe he was primarily a violin-family maker and used a violin style tapered joint like the Hofner instruments. That would jibe with your neck block description.
If you separate the fingerboard extension from the soundboard it should practically fall apart in your hands.
Yes, I was surprised to see the spruce block. At least it is removable, in theory, in case a neck reset is needed(I can't string it up to tension yet, because the neck heel glue joint-not the neck to body joint- has separated, and needs to be reglued).
Yes, I understand. Are you going to try to reglue the heel without removing the neck? Might work fine; it was probably glued with hide glue, but if you took it off you could clean the joint and maybe add a vertical spline for insurance.
I would prefer to remove the neck, to reglue the separated heel: I believe it will be a better fix. The joint is open, but not enough to coat the entire glue surface with fresh glue.