I had to make a new key foot/hinge tube for the low D key of a Selmer alto sax.
The one that was on the instrument was not original, and was mangled so that it would fit, which you can see by how chewed up the original tube was.
In addition, it didn’t fit the instrument: it was bumping into a nearby post, which the original tech tried to fix by cutting a big chunk out of the post.
You can see this in the photo of the incomplete key on the instrument.
The replacement key was cut out of raw brass, shaped, then brazed together to match the existing keys.
A comparison between a different key with the original Selmer geometry, and the key I made.