"This door must satisfy three core requirements: its sealing must be good enough to isolate cold air to the maximum extent."
"It must be robust enough to withstand the gales of the Labrador Coast, and even endure the probing of a curious black bear."
"Without modern metal hinges and nails, its rotating structure must be simple, reliable, and durable."
"I will adopt a design I call 'cross-pin hinge.'"
"All of its weight-bearing relies on a few sturdy wooden pins and slots, completely eliminating the need for a complex pivot, making it easier to construct."
"But to achieve this design, I need to perform some relatively precise drilling work. Therefore, I must upgrade my toolbox before making the door."
"I plan to create something less labor-intensive—a pump-style hand drill."
Facing the camera, he explained: "Its structure is more complex than that of a bow drill. It requires making a drill rod, a crossbar, a flywheel, and a handle."
