Deadbolt cylinders for the 'tubular' type deadbolts shown here are normally not interchangeable with anything other than another lock of the same brand, even if they do appear almost identical. The tailpieces do not turn in the same way as a fixed tailpiece on a knob or lever cylinder. In order for the thumbturn or cylinder on the inside to operate, the tails must be able to rotate independently of the cylinder they are attached to. This is sometimes referred to as a 'lazy' cam or tail. You will probably not find a replacement cylinder for a cheaper deadbolt, the locks are so cheap there is no point. With any decent brand name lock you should not only be able to obtain a replacement cylinder from a locksmith or lock supplier, but with many there are high security retrofit cylinders available. As with all the other cylinders, avoid buying a lock that uses die cast material for the cylinder.

  These images show the cylinder in and out of the shell. It is held in place by one screw on this lock, an Arrow E61. By using different tailpieces on the cylinders, they can be set up for a double cylinder lock. Some of the better quality Schlage cylinders even have different tails to convert their cylinders for use in knobs and levers. The tailpiece on the single cylinder version shown here extends into the thumbturn on the inside of the door, and is marked and notched to accomadate different door thicknesses. Double cylinder tailpieces are shorter and overlap each other as they pass thru the locking bolt, or as in the case of Kwikset, a smaller tail on one cylinder slides inside of the larger tail on the other cylinder.