Double cylinder assembly machines automatically insert all bottom pins, top pins, and springs into both sides of the double cylinder. After testing for proper parts load and successful rotation test of the external cylinder, the pin holes are closed using either a strip, a cover, or closing plugs. An LVDT key reader measures the key cuts to obtain the pinning information.  Alternately, the key codes may be obtained from a file. An operator manually loads the empty cylinder and the cut key into the machine. Assembled cylinders are automatically unloaded into a chute.