There are several types of crankshafts used in manufacturing, including single-piece, two-piece, and three-piece crankshafts. Single-piece crankshafts are the most common and are typically used in smaller engines. Two-piece crankshafts are used in larger engines and are made up of a main journal and a crankpin journal. Three-piece crankshafts are used in very large engines and are made up of three separate pieces that are bolted together.