11/09/2026
A lady poured cooking oil into her front door lock. I want to say straight away that she was not being daft, and by the end of this you might see why.
Her door had been getting harder to lock for months, so she did what more or less anyone would do. She looked it up. And every single page she would have found says the same thing: a stiff lock needs lubricating.
So she lubricated it, with what was in the kitchen cupboard. Not a drop on a cotton bud either. Bottle poured, down the edge of the door and into the mechanism. And here is the part that turned a small job into a big one: the stiffer it got, the more she poured. Every time it got worse she assumed she had not used enough.
By the time I had it apart, everything inside was glued together. Cooking oil goes tacky, then solid, and on the way it grabs every bit of dust in the door. There was nothing to clean and nothing to free off. It needed a whole new mechanism, and the cylinder with it.
(My advice on cooking oil is to use extra virgin olive. I want to be very clear that I am joking.)
Now here is the awkward bit. I am a locksmith about to tell you not to buy lock lubricant. Bear with me.
Open the box on any lock I fit and have a look inside it. A euro cylinder, a mortice lock, a multipoint strip. They come dry. No oil, no grease, nothing. That lock goes on the door dry and it works perfectly, and it carries on working perfectly for years. I have had cylinders and multipoint mechanisms apart that were twenty and thirty years old and had never been oiled in their lives. Not once. All still working.
So if your lock did not need lubricant when it was new, why would it need it now?
It does not. Something else has changed, and the oil just hides it.
Seven times out of ten the thing that changed is the door, not the lock. Doors drop on their hinges. Frames settle. Sometimes the building itself has moved, quietly, over thirty years, without ever announcing it. The keeps go out of line by two or three millimetres, which is nothing to look at and everything to the hook that has to find its way in.
The other three times out of ten, it is a mechanism nobody has ever cleaned. Which is why cleaning comes first and lubricating comes second, and almost every guide you will read online skips straight past the cleaning.
And this is where it starts costing money. A door that has dropped a few millimetres is usually a small job. But every time you force it shut, or heave the handle up against the resistance, all that load goes through the gearbox in the middle of the mechanism. It puts up with it for a while. Then something inside gives up, and it is always on a cold morning when you are already late.
If you do want to put something in, here is the only rule that really matters. Never mix lubricants. Not graphite on top of a spray, not a spray on top of graphite, not a new can on top of an old one you cannot remember buying. Pick one and stay with it.
Locks very rarely fail because somebody used the wrong product. They fail because somebody used four.
Silicone lubricant or PTFE lubricant, cleaned first, once or twice a year, and that is genuinely it. One can, bought once.
Full thing here, including the twenty minute service and the five things worth checking while you are there: https://andrewthelocksmith.com/lock-lubricant
If your door has started needing a shove, get it looked at while it is still an adjustment. It is a much smaller job in September than it is in January.
Call Andrew: 073 7617 6366