A CNC spindle spins at tens of thousands of revolutions a minute, and when it fails the machine stops, the part is scrapped and a technician is called at two in the morning. Torquewell puts a small sensor on the spindle housing and listens. A bearing begins to wear weeks before it fails, and it makes a sound.

Marco DeLuca ran a machine shop for nineteen years, and he built the first prototype from parts in his own tool crib. The sensor clips on, needs no connection to the machine’s controller, and sends one message to the maintenance planner: this spindle, about three weeks.

The company is now monitoring about 900 spindles at 52 shops, and its alerts have caught more than 300 failures before they stopped a line. Most customers started with ten sensors on their most expensive machine.