The Importance of a Smooth Shank

What happens here

The video explains that many construction screws are not fully threaded all the way to the head; they feature a smooth, unthreaded shank. This smooth section is crucial for effectively clamping two pieces of material together. The presenter demonstrates the difference by first driving a drywall screw, which is fully threaded, into two pieces of wood using a Milwaukee impact driver. He shows that because the drywall screw's threads grip both boards, the top board cannot slide freely, and it doesn't pull the boards together as effectively. In contrast, a construction screw with a smooth shank allows the top board to slide freely along the unthreaded shank, while only the threads engage the bottom board. This design ensures that as the screw is driven, the head pulls the top board down while the threads bite into the bottom board, effectively pulling the two pieces of lumber together tightly without drawing them apart.

Goal: Grasp the functional benefit of a smooth shank in clamping materials.