A locksmith cylinder puller removes the cylinder in the doorknob that provides entry to the lock body. If the key to a door with a bored cylinder-lock is lost, a puller can take out the cylinder without damaging the hardware.
A cylinder puller requires a pair of small flathead-screwdrivers and an Allen wrench. This puller works from inside the doorknob. The doorknob must be removed from the door for the puller to work.
Place the Allen wrench between the spring on the outside of the cylinder housing and the bolt shaft. One flathead screwdriver is pressed against the shaft, and run down into the housing as far as it will go. The second flathead screwdriver is pressed against the lip of the housing, and run down as far as it will go. Both screwdrivers press against the internal walls of the cylinder housing.
The flathead screwdrivers depress the spring-locking clips and pull them away from the internal walls of the cylinder housing. The clips secure the housing to the knob body. The cylinder pops out of the knob when the spring clips are pressed inward.