Its a mostly simple job to fit a new lock barrel. The lock itself is not replaced, just the barrel, which is bought separately.
==Why== Apart from the obvious:
A new lock barrel is under £2 for a basic one, or £4-5 for one with hardened pins in 2011. So replacement is often cheaper than copying keys. New bzrrels usually come with 3 keys, sometimes 2.
When moving into a house, you've no idea who has keys. Its prudent to replace external lock barrels.
Some house insurance policies are invalid if a barrel with unhardened pins is used on an external door.
==Gain access== If you're locked out and can't get in any other way, drilling out the lock barrel is usually the easiest way to gain entry. Expect to ruin a few drill bits in the process. 4mm twist drills are good for the job, though if not careful more drill bits will be needed.
==Remove lock== There are 2 ways cylinder locks are commonly fixed to doors. Remove the visible screwheads, and either the whole lock will come off in one piece, or most of it will come off, leaving a backplate behind that needs to be unscrewed to remove it.
==Remove old barrel== As you'll see, the lock barrel is held with 2 screws. Remove these and the barrel, the ring on the front, and the plate on the rear come away. Reuse these screws if they're not wrecked, its easier than cutting the new ones to length.
==The new lock barrel== They're standardised, so the main choices are brass or chrome finish, and hardened or unhardened pins. * minimum cost barrels are unhardened, and can be drilled open * house insurance often requires hardened pins * hardened pin barrels can be drilled, but its more difficult, and can take a while, and several drill bits. * unhardened may be preferable for internal rooms & cupboards, a fair bit easier to remove if keys are ever lost.
Its not best practice to have new locks, barrels or keys posted to you, the seller usually has your address, either from the delivery address or credit card details, and there are people that copy keys and misuse them.
==Fit new barrel== How it fits in is fairly obvious, ring at the front, plate at the back. Get the new barrel in the right position, not twisted round out of place. There's usually a slight ring indentation in the door, you sit the front ring in that to avoid a minor decorating mishap. Often the old front ring looks better than the new one, and on occasion the old rear plate is the only one that will sit flat enough.
Reuse the old barrel fixing screws when possible, it avoids needing to cut the new ones. If they can't be reused, the new ones can be chopped or sawn at the indentations. Don't try to snap them by bending, a lot of these screws aren't hardened and will bend, ruining them instantly.
The tongue of the new barrel needs to be cut to length. Mark on the tongue where it projects about half the depth of the lock, and cut it off there. Length needn't be precise. A hacksaw works, but is slow and fiddly; bolt croppers or mini bolt croppers are very quick.
==Refit lock== Just the reverse of removing it.
==Issues== Issues sometimes encountered:
The new lock is too stiff to turn as far as is needed. If it turns in one direction ok, and opens the lock, no problem. If not, slacken the lock barrel fixing and slide it sideways a fraction so it lines up better with the slot in the lock, and retighten.
The lock screws won't tighten because the thread in the wood is stripped. Probably the simplest solution is to lightly hammer a matchstick into the hole in the wood door, and snap it off level. Or sometimes slightly fatter screws will fit and grip. Or if the screws are short, fit long ones.
Lock won't quite sit flat against the door. This happens when the rear plate that holds the lock barrel fouls the lock. Loosen this backplate, reposition slightly and tighten, or remove it and put the old one back on instead.
In some situations you might need the new lock to take the old key. Rekeying a lock barrel is a locksmith's job.
==See also== * [[Special:Allpages|Wiki Contents]] * [[Special:Categories|Wiki Subject Categories]] * [[Door security]]
[[Category:Basics]] [[Category:Doors]] [[Category:Repair]] [[Category:Security]]