How to calculate the outer diameter of gear : Gear Diameter = (number of teeth + 2) * Modulus For example(0.5Modulus, 10T): Gear diameter= (10+2)*0.5=6mm ----------------------------------------- How to calculate the modulus of gear : Modulus= Gear Diameter/(number of teeth + 2) For example(6mm Outer Diameter, 10T): Modulus= 6/(10+2)=0.5 Material: Brass