From time to time I see complaints about the thumbrests on vintage horns, and I thought I'd share what I've learned about differences between modern and vintage ergonomics. Maybe it can help you if you deal with some of the same issues I did.
The silver sax on the left is a modern Yamaha, with what we've come to think of as a "normal" thumbrest. The beauty queen on the right is a 60's Conn 10M. Chief amongst complaints with 10Ms are the "vintage," or "tortuous" thumbrest, and the neckstrap hook position, placed in the ideal spot to remove your front teeth. The complaint is that these vintage thumbhooks cause pain, are not ergonomic, or are poorly designed. I claim that these are well thought out, well placed, and problems arise when someone comes from playing a modern horn to a vintage one. The issue is that the two horns are meant to be held differently
I think of the difference between the two as holding a book, and holding a can of beans. I suppose you can substitute any canned product. If you look at the shape of your hand holding a book, you'll notice that your thumb is flat, with the tip of the thumb slightly curved:
Thumbrests on modern saxes are designed to be used in a hand position like this. The hook comes over the knuckle, and you can apply pressure to get the horn in position.
Vintage horns require the can of beans method. Notice how the thumb curves around the can, and the tip is bent in toward the can:
With the hand on the horn, the hook sits just past
the knuckle, and the pad of the thumb tip rests on the body of the sax.
I think, given the way the two horns are balanced, their respective thumbhook designs make perfect sense. On modern horns, the horn's unsupported position is more horizontal. The player pushes with his right thumb to get the horn in playing position, so that the horn is more directly in front of the player. This can be a more natural playing position when you are standing.
A vintage horn will balance unsupported more vertically. This is where you can lose your teeth if you're not careful. While standing, the natural position is for the horn to be a little off to your right.
If you're used to playing modern horns, and try to keep it straight in front of you, you're asking for thumb problems. Playing while seated, though, it is a very comfortable position. The horn need to only be lifted slightly away
from the player's body; this is why the vintage thumb position makes sense to me. Pure speculation here, but I think this is the root of the difference: as styles of music changed, sax players went from playing in dance bands, seated, to standing in front of jazz combos. Or at least that's how the conception of the "sax player" changed over time.