Perimeter bolts

Perimeter bolts are the locking points spread all round the edge of the door: on the lock side, at the top, at the bottom and sometimes on the hinge side. Some are driven by the lock when you turn the key and others, which are fixed, engage when the door closes.

They are typical of security doors and armoured doors. By anchoring the door leaf to the frame on several sides, they make it very hard to lever open, because the tool cannot find a weak point.

For them to work properly, each bolt must go straight into its hole without rubbing. If the key goes stiff at the end of its travel, or you have to push the door to lock it, one of the bolts is out of adjustment. We cover this under lock installation and multipoint locks.