Profile: M and B Gears and Engineering specializes in offering precision machining , gear cutting, precision measurement, and assembly & fitting services. We specialize in gear manufacture, motorized pulleys, and general engineering services. Splines are used in mechanical rotating drive systems. Parallel key spline type has equally spaced teeth that are straight sided. The teeth on the shaft have an equal tooth thickness at any point measured radially out from the axis of rotation. Conversely, the internal parallel spline has parallel spaces.