Start by using a little bit of lubricant and apply more if the lock still sticks.
Sticky lock on front door.
Handle powdered graphite carefully.
Just gently squeeze a very small amount of graphite powder into the keyhole and then use your key to slowly work the lubricant into the lock.
The fix in instances with a door latch stuck because it is jammed by rust and other materials it is always best to disassemble the lock and do a bit of cleaning.
Pull both door knobs away from the door.
Spray a couple of shots of spray graphite on the latch mechanism where you see a seam.
Sticking door locks can be attributed to everything from slight settling of the house to a buildup of dust and dirt within the locking mechanism.
Remove the two screws on the inside door knob faceplate with a phillips screwdriver.
Hold the front door knob with one hand and the inside door knob with your other hand.
Do not over tighten the screws or you may strip break them.
Tighten the screws that go into the door and the screws that go into the door frame.
Tightening hinges on a sticking or sagging door loose hinges are the primary causes of sagging doors.
Fortunately most front door lock problems can be.
And when doors sag they tend to stick because they rub against the door jamb on the latch side of the door opening.
Almost all sagging doors are due to loose hinges.
The problem however is that oil or grease will eventually make the sticking lock worse.
Another way to do it is to coat your key with the graphite powder first and then simply insert it into the lock.
Use the right product resorting to spraying vegetable oil wd 40 sewing machine oil or similar products in the keyhole is a fairly common fix.
Below are 3 tips to fix sticky locks.