2. FERROUS METAL  Steel  Stainless steel  Cast iron  Powder Metal NON-FERROUS METAL  Aluminum  Titanium  Brass

3. PLASTIC  Polycarbonate  ABS  Nylon  Delrin  Polyethylene  Polyamides COMPOSITE  Carbon Fiber  Fiberglass  Kevlar  Thermal plastic embedded with fibers

4. PLASTIC  Low production cost  Good strength to weight ratio  Multiple material options to meet the needs of the gearbox.  Quiet mechanical operation COMPOSITE  High production cost  Highest strength to weight ratio  Multiple composite options  Quiet mechanical operation  Subjective to mechanical wear

5. METAL  High strength  Long life  Lubricated to prevent wear  High RPM capability  Moderate manufacturing needs  Brass gears are soft and quiet.  Aluminum gears are harder and have more mechanical sound than brass  Steel gears are the hardest and have more mechanical sound.

6. WHICH MATERIAL?  Gears should be selected based upon the use of the gearbox.  RPM, weight and temperature are just as important to considerations as the load in which the gears will transfer  Manufacturing ability and project cost often dictate the materials that gears are made of.  Choose the material that best meets the need of your project.