Interlocking Teeth
Interlocking teeth are the fundamental mechanical components that enable zippers to function by meshing together in a secure, continuous line. Each tooth on opposite sides of a zipper slider is precisely shaped and positioned so that when the slider moves along the track, it forces the teeth from both sides to interlock, creating an effective seal. The geometry of these teeth is critical to the zipper’s performance—they must be uniform in size and spacing, and angled correctly so they catch and hold without jamming or misalignment.
Design and Manufacturing
The design of interlocking teeth involves careful engineering of tooth profile, pitch (the distance between adjacent teeth), and material selection. Teeth are typically manufactured from metal, plastic, or nylon, each with different advantages regarding durability and cost. The teeth must be produced to extremely tight tolerances to ensure consistent meshing; even minor deviations in size or spacing can cause the slider to jam or fail to seal properly. Modern manufacturing processes use stamping, injection molding, or extrusion depending on the material and intended application.
Mechanism of Interlocking
When the slider is pulled along the track, it compresses and forces the upper and lower rows of teeth together. The angled sides of each tooth guide the opposite row into interlocking position, while the slider’s internal structure—typically containing a hollow channel—ensures the teeth stay aligned and pressed together. As the slider moves backward, it allows the teeth to spring apart and disengage. The success of this mechanism depends entirely on the precision and consistency of tooth geometry across the entire length of the zipper.
Source Notes
- 2026-04-08: Why are these 3 letters on almost all of my zippers?