Cylinder assembly machines automatically insert all bottom pins, top pins, master pins, and springs into a lock cylinder. Bottom pins and top (dumbbell) pins are loaded by auto feeders and springs by one spring box. An operator manually insert one cylinder inserted with one cut key, a LVDT key reader measures the key cuts to obtain the pinning information. Alternately, the key codes may be obtained from a file. Springs will be loaded on another station and checked whether they stay inside the pin holes. Assembled cylinders are automatically unloaded into a chute. Customer can choose whether to use brass strip or brass pins to close the pin holes by hydraulic punching mechanism. Complete assembled cylinder can be checked if closed correctly and unload to the chute or to the operator when NG. Machine A101 performs the same functions as machine A100, except machine A101 loads the components from inside of the cylinder.