"So he teaches me."
"You've never touched a lathe."
"Ask him," she said. "If he says yes, I want to talk to him and the shop owner myself about safety. And Desmond, this still doesn't matter unless the form comes in."
"I know."
"I'm saying it because you're eleven and you'll want to make the gear the answer to everything. It isn't. It's the answer to the gear."
---
He found his grandfather in the lobby of their building after school, sitting in one of the leather chairs by the mailboxes, reading the Democrat and Chronicle with the crossword folded on top.
"Grandpa." Dez dropped his backpack. "Can you still run a lathe?"
Walter lowered the paper. He looked at Dez for a long moment over his glasses, and his face did something complicated, the way a face does when somebody says a name it hasn't heard in a long time.
"Why do you ask me that?"
Dez held out the gear with its missing tooth. Walter took it and turned it over in his fingers, close to his eyes, then held it toward the light from the revolving door.
"Thirty-two pitch," he said, almost to himself. "Twenty-tooth. Fourteen and a half degree pressure angle, probably. Case hardened. Somebody overloaded you." He looked up. "Sal still has the South Bend. And a dividing head, if he didn't sell it. You'd cut the teeth on the mill." He stopped. "I'm not allowed to make it for you. Is that right? That's a rule?"
"How do you know that?"
"I've been volunteering at the district build hub since September," Walter said. "Saturday mornings, with the high school teams, before your session starts. I show the big kids how to file a burr and I keep my mouth shut. Ms. Sato runs the hub. She ran my clearance in the fall." He held up a hand at Dez's face. "I'm gone by the time you get there. I didn't tell you because you'd have been watching me instead of the robot. And I didn't tell your mother, because—" He stopped again. "Because I didn't."
Dez stared at him. He thought about every Saturday since fall when Walter had dropped him at the door at noon, smelling faintly of cutting oil, and said he'd been running errands. Dez had never asked what errands. He'd been thinking about the robot.
"You smelled like oil."
"Cutting oil. Smells the same for fifty years." Walter handed the gear back. "Tonight. After dinner. I'll call Sal."