Tavin laid three rib blanks on the rib bench and tapped each one with a steel rod.
The rib bench was a short heavy table in the corner of the Quiet Forge’s outer hall, its top a single slab of iron, scarred by a century of hot work. Tavin had cleared it at the fifth hour and laid the blanks on it side by side. Three bars of alloy, each the length of his forearm and as thick as two fingers, cut from the yard’s spare stock. For the seventh channel’s bracing. The ribs that would hold the spiral’s curve from outside when the return took load.
He took the steel rod from his apron. A plain round bar, a hand long, polished at one end from years of this. He lifted it and tapped the first blank near its end.
It rang. A clear high note that hung in the hall over the old heart’s ragged tone through the wall.
He tapped the second. It rang true too. The same note, near enough.
He tapped the third.
It gave a flat note. Dull. Short. Like a cracked bell.
Tavin set the third blank aside on the floor without a word. He did not argue with it. Mara watched him do it, from the main bench where the replacement heart’s frame sat with its seven channels.
