By Will Gish — Updated March 24, 2022
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A spur gear is the most fundamental gear type. Its cylindrical body with teeth running parallel to the axis makes it highly versatile—from automotive transmissions to household appliances. The frequency of use demands materials that are both easily fabricated and exceptionally durable.
Acetal, also known as polyoxymethylene (POM), is a high‑strength plastic that can be molded into intricate shapes, including gear teeth. Its superior stiffness, low friction coefficient, and excellent wear resistance make it ideal for medium‑speed applications where noise reduction and dimensional stability are critical.
Cast iron offers a cost‑effective solution with good wear resistance and high load capacity. Its composition—typically a mix of iron, silicon, manganese, and carbon—provides inherent strength while remaining relatively easy to cast. However, the exact mechanical properties can vary between batches, so specification sheets should be consulted for each application.
Stainless steel, an alloy of iron, chromium, and nickel, combines corrosion resistance with high tensile strength. The chromium content forms a passive oxide layer that protects the gear from rust and surface scarring. This material is preferred for high‑speed or chemically aggressive environments where both strength and longevity are paramount.
