What the key is telling you

Lock care begins with one habit: taking the resistance in the key seriously. In a new cylinder the key turns smoothly. Over time dust, micro debris from the plating and old oil that has dried form a paste between the pins, and that is where resistance comes from. Forcing the key works at that stage, but every forced turn starts to bend the key itself. One day it snaps inside, and this is no longer maintenance.

What belongs inside a cylinder

A cylinder is a set of small pins working to tight tolerances. Anything thick or sticky in there collects dust and makes matters worse. So dry lubricants are the right choice: graphite powder, or a PTFE based dry spray made for locks. They keep things moving without attracting dirt.

What does not belong is equally clear. Grease and heavy machine oil slow the pins and stiffen in the cold. Vegetable oils eventually turn to resin. Multi-purpose penetrating sprays dissolve old oil and bring temporary relief, but they leave no lubricant behind, so the lock runs drier a few weeks later; use one as an emergency measure and follow it with a proper lubricant.

Application is simple. Give the keyway a short burst or a very small amount of graphite, turn the key through full rotations several times, then wipe away anything that escapes. Residue on the outside of the cylinder marks the door face.

The mechanism in the leaf edge

The cylinder is one part of the lock. Behind the faceplate on the leaf edge sit the bolts, the drive links and the return springs. Those parts run metal on metal, so light machine oil or a suitable grease is correct there; unlike the cylinder, stickiness is not a problem.

Oil goes where the bolts travel in and out of the leaf, and into the latch housing if there is one. Oiling the exposed faces of the bolts achieves nothing and transfers marks to the frame when the door shuts. A dry cloth and a thin film are enough there.

Do not forget the keeps

A fair share of jobs reported as lock failures start in the frame. If a keep plate shifts, or fills with dust and paint, the bolt no longer seats and the key turns hard. Cleaning the keep mouths once a year, checking the plate screws and looking at whether the bolt enters centrally extends the life of the lock more than anything done to the lock itself.

What changes on a multipoint lock

A multipoint lock works at several positions along the leaf, linked by a drive bar. Two extra checks follow. First, whether all points move together when the handle is lifted; a point lagging behind means the drive connection has slackened. Second, whether each point enters its own keep centrally. One point under strain tires the whole mechanism, because the force travels along the bar to the others.

Turning the key before lifting the handle strains a multipoint system. The sequence is always handle first, key second.

How often

  • Monthly: notice how the key turns, and note any new stiffness.
  • Every six months: dry lubricant in the cylinder, light oil in the leaf edge mechanism.
  • Yearly: clean the keep mouths and check the plate and faceplate screws.
  • Yearly: light oil on the hinge pins, since alignment affects the lock directly.
  • Whenever a key is copied: take the burrs off the new key with fine abrasive.
  • After a move or building work: an extra clean and lubrication for the dust.

Keys wear out too

The most overlooked part in lock care is the key. Carried in a pocket for years, its cuts wear down, and a worn key cannot lift the pins to the right height. A hard turn is not always the lock's fault. If you have more than one key, try the least used; a difference proves the key is the problem. Cheap, badly cut copies do the same thing and scrape the inside of the cylinder as a bonus.

What oil will not fix

If the key only goes halfway in, something is broken or lodged inside. If the key turns but the bolts stay put, a drive bar or link has failed. If the handle will not drop, or stays up, the return spring is tired. If the lock turns with the door open but not closed, the problem is alignment rather than the lock. In those four cases, lubricating is lost time; the mechanism has to be opened.

If a cylinder needs replacing, note its body dimensions and the door thickness. If you are considering a new door, send your opening measurements and we will propose options from luxury steel doors or ultralam steel doors complete with lock hardware. For a shared entrance, multipoint and electrified options sit under building entrance doors and are quoted with the hardware you choose.