"Use the line from Twelve. Twelve's the same year as Thirty-One. Same fitting." He took the line out of Ray's hand and set it on a separate shelf, the one with a strip of tape on the edge that said *DO NOT USE — CHECK.* "Just because a part goes on doesn't mean it belongs there. That's the whole job, right there. Knowing the difference."
Ray looked at the shelf. It already had a dozen parts on it.
"Those are all parts that fit," he said slowly. "But are wrong."
"Or that might be wrong. I don't know yet. So they don't go on anything until I do."
---
There were moments in those weeks when Ray watched his father and saw something he had not seen since he was a boy.
He saw it in the way Earl held a part up to the lamp, turning it slowly, his face completely still, the way a jeweler examines a stone. He saw it in the way his father would stop in the middle of a task, set down his wrench, and open one of the old notebooks, flipping through yellowed pages until he found what he was looking for, then nod once and go back to work. He saw it in the way Earl talked to the machines under his breath sometimes, not in words exactly, more like the low murmur a man uses with a nervous horse.
And he saw it in his father's hands. They were old hands now, spotted and knuckly, the skin thin over the veins. But they did not shake when they were working. They moved with a confidence that had nothing to do with strength and everything to do with having done a thing ten thousand times, until the knowledge was not in the head anymore but somewhere deeper, in the fingers and the wrists and the palms.
"How do you remember all this?" Ray asked one evening, when they were washing up at the utility sink.
Earl dried his hands slowly on a red shop rag.
"I don't remember most of it," he said. "That's what the notebooks are for. But you do something long enough, you start to know when something's wrong before you know why. You pick up a bearing and it's too light. You hear a pump and it sounds a little high. You look at a seal and the color's off. Then you go find out why." He folded the rag and hung it on the edge of the sink. "Forty years of finding out why. That's all it is."
"That's not all it is, Dad."
His father looked at him, and for a second Ray thought he might say something more. Instead he just nodded, and turned off the light over the bench.
The tractor was finished on the first Saturday of December, and Earl waited until Ray and Megan were both there before he tried to start it.
He did not say that was why he waited. He said the battery needed to finish charging overnight, which was true. He said the hydraulic fluid needed time to settle, which was also true, sort of. But when Ray and Megan pulled into the yard a little after nine that morning, they found him sitting on an overturned bucket in the open doorway of the machine shed with a thermos of coffee, doing nothing at all, and it was clear he had been sitting there a while.
The tractor stood in the middle of the shed floor, and Ray stopped short when he saw it.