High Security Locks: preparing for the visit

You have lost count of how many people have had a key to your house over the years: cleaners, a contractor, a former partner, the previous owner's family. The lock still works, but you no longer know who else it works for.

Worth answering before the call

For a business, who should be allowed to authorise new keys? Is there a window or sidelight within reach of the lock? Does the door drag, stick in cold weather or need lifting to lock?

What are the hardware grades I see on the packaging?

Locks and deadbolts are tested against industry standards for security, durability and finish. Commercial hardware is graded 1, 2 or 3 with grade 1 the highest. Residential hardware carries a letter label for each of the three categories, from C for good through B to A for the top level. Security tests include hammer blows and pulling on the lock; durability covers cycle life and seasonal misalignment; finish covers salt, humidity and scratching. Your locksmith translates the label for your door.

Will the new cylinder fit my existing locks?

Usually. High security cylinders are made in the common formats: key-in-knob and lever, rim, mortise and interchangeable core, and many are designed to drop into popular residential and commercial locks. The locksmith identifies your format and confirms fit before ordering. Where a lock is an odd size or in poor shape, a matching lock body is fitted instead, and the door preparation is reused wherever it is standard.