One of the senior engineers, a gray-haired man near the back, exhaled audibly. He pulled out his phone and started scrolling through the firmware change log. His face told the room everything.
Ivory set the flex splines down and moved to the lubrication system. She unscrewed a grease fitting on the side of the harmonic drive assembly. A small amount of lubricant dripped out onto a white shop cloth she'd laid on the workbench. She held up the cloth.
"This is NLGI grade three grease: heavy, stiff, designed for slow, high-load applications—things like wheel bearings, mining equipment, open gears that turn a few times per minute."
She pulled the tube of grease from her backpack and squeezed a small amount onto a second cloth.
"This is NLGI grade one: semi-fluid, designed for high-speed precision mechanisms, exactly what a harmonic drive is. This is what the manufacturer specifies. This is what should be inside that machine."
She held both cloths side by side. Even from across the room, the difference was visible: the grade three was thick and pale, almost like putty; the grade one was darker, smoother, with a consistency closer to heavy cream.
"Grade three grease in a harmonic drive is like putting honey in a watch. It increases internal friction by a factor of three. It raises the operating temperature by 8 to 12 degrees Celsius, and it accelerates exactly the kind of resonant fatigue I just showed you, because hotter metal fatigues faster."
She opened her notebook to another page, a procurement record Nathan had helped her access.
"Six months ago, the lubrication specification for all SD9 units was changed in the procurement system from NLGI grade one to NLGI grade three. The reason listed was cost reduction. The annual savings: $11,000 across all units." She held up the page so the board could see the line item, then she read the authorization signature at the bottom: "'Approved by the office of the vice president of engineering.'"
She didn't say Brent's name. She didn't need to. Every head in the room turned toward him. Brent's face had gone the color of old paper. His mouth opened, but nothing came out.