Prosthetics
Clockmakers build them, and the work is among the finest anyone in the world does — springs and linkages refined over nine centuries by guilds who never found anything easier to do instead. They are described here rather than under Clockwork because what matters about a prosthetic is the person wearing it.
The hand
A harness across the shoulders, a cable, and a hand at the end of it. The hand sits closed on a spring, because a grip that holds without effort is worth more than one that must be maintained, and the cable opens it when the wearer moves his shoulder in the way he was taught. Better hands offer a few modes set by a lever before he reaches — a pinch for a pen, a wider hold for a cup, a flat palm for carrying — and the finest give the thumb its own cable. The wrist turns against a detent and stays where it is put; the elbow locks under load and releases when he shrugs. The hand itself comes off: a hook for work and a dressed hand for company share one keyed collar at the wrist, and a practiced wearer changes them with his sound hand in a few breaths. The dressed hand is carved, painted, and gloved, sometimes with a touch of Glaera at the nail-beds so it reads in poor light.
The leg
A knee that locks under weight and releases to swing; on the better legs a sealed oil damper slows the swing so the foot does not slap, and a linkage shortens the leg as it comes through so the toe does not catch. Every leg is built for the ground its wearer works — a deck, a quarry stair, a paved street — and a leg made for one is poor on the others.
The socket
The limit of all of it: leather molded over a form, or a thin metal shell lined to the stump, cut away where bone bears and padded where it must not. A poor socket makes a brilliant hand unwearable, which is why a fitter follows the same person for decades. Higher losses cost more, and many wearers refuse the bargain and keep a simpler rig.
What it cannot do
None of it reads intent and none of it feels anything. Every action is something the wearer does on purpose with a part of himself that still works, and he watches what he is holding because nothing tells him how hard. A few makers run a taut thong from the hand to a patch of skin on the stump so that a knock or a heavy close is felt as pressure — crude, easily ignored, and treasured by those who have learned it. Learning takes months and some never get on with it.
Who makes them
Stormharbor designs the best, because Stormharbor has the most use for them, and commissions the fine parts from Forgegate. Its boat hand has fewer joints in a sealed housing and a grip meant to close on a gunwale and stay closed when the deck moves. Stormharbor is also where most of the world's few bone pins are — a rod through the skin into the bone, for people who have ruined every socket and would sooner risk the pin than give up the work; infection is the price and nobody calls it safe. A good hand is fitted to one person by a maker who does nothing else, cased in brass, marked, and built to be serviced rather than replaced. A man who has worn his twenty years has had it apart twice and knows the repairman by name. A prosthetic is an instrument somebody has to learn to play.