In the course of my work, I often find myself beefing up the security features on entry doors. In addition to adding a deadbolt, I like to add a reinforced deadbolt strike plate. I attach it, and the door hinges, with 3-in. screws.
Some doors are hung with their hinge pins vulnerable to the outside, inviting a break-in. Rather than resort to unsightly pins that protrude from the door jamb, I simply add (or replace) a hinge mid-height on the door with a fixed-pin hinge. Once this hinge is installed with 3-in. screws, the edge of the door is secure from inside or out. A carpenter needing to remove the door simply removes the screws from one leaf, and then has the convenience of two loose pin hinges while planing, or re-hanging the door. Once those screws are back in, the door is there to stay.
Kurt Lavenson, Berkeley, CA