Could be several things. Worn key, worn lockset, or dirty lockset. I'd bet dirty lockset.
First thing I would do is clean it, spray info the keyhole with a dry lube such as PB Blaster dry lube w/ teflon or wd-40 specialist silicone... then give it a good shot of compressed air to dry it out. Followed by a shot of graphite powder. Work the key, give it another shot of graphite. Do not use oil. If that doesn't fix the problem it's likely a worn key, especially if other keys work fine. If you have to jiggle all keys... dirty lockset.
I had a lock like that. A squirt of WD-40 every six months kept it working for years. Previously I had tried graphite powder but this lock was outside and exposed to the weather and corroded a bit inside. The WD-40 seemed to cut through the corrosion better and got the lock working more smoothly than graphite.
I have to agree with the 'lubricate' as that generally works for several years. But I need to add 2 things:
FIRST- prequel-
Back in the mid 80s, my parents bought an early 1970s former 7-11 store that had been converted to 7-11/Southland regional office, to use as office space for OUR family businesses: insurance/investment - real estate.
At settlement the property was turned over broom-swept-clean and we got a set of keys to the building- standard practice. THEN the seller handed over "THE KEY' to the front door.
Apparently, then the locksmith installed the front door, he cut 2 keys, the owner gave 1 to the manager who then used it every day, and occasionally make copies for assistant managers.
The owner took the 2nd freshly cut key, tossed it in a safe or safety deposit box, and every couple of years he'd use THAT pristine key to cut a new copy for the manger.
SECOND -sequel-
If you look at most newly cut keys, the tips are sharply angled 'teeth', which wear down with use. I've seen a very interesting work-around / restoration technique for old worn keys. (Apparently, the metallurgy of locks is setup so that the pins are harder than the key, so the keys wear down.)
Eventually the 'valleys' in the key get 'worn down' and the key needs to be jiggled.
BUT- there appears to be a VERY interesting way to fix this:
I've heard that you can scan-in the dimensions of a worn key, and then use 3D printer modeling software to extrapolate the original key profile, THEN print a plastic version of that key using a 3D printer.
While the plastic key will work, the better practice is to take the 3D printed plastic 'extrapolation' and go to the hardware store key-cutter and cut a steel key that has a brand new key-profile'.
Last edited by PJmax; 04-12-23 at 12:31 PM.
Reason: resized pic
Lubrication - Dry graphite is the preferred lubricant; WD-40 attracts dust. Agreed, first action should be to lubricate. Wear - A couple of possibilities:
1. Each time you insert/withdraw a key, both the key and the pins inside the cylinder pick up some wear. The front pin in the lock and the tip of the key get the most wear. Over time that wear can cause your problem. 2. You are using a duplicate key that was cut too deep. Duplicating a worn key just gives you a shiny new worn key.
If lubrication doesn't solve the problem, take your key and have it duplicated with two layers of paper underneathyourkey (this makes the duplicate a few thousandths more shallow); this may very well solve your problem. They will probably argue with you, but be insistent.
In keeping with the spirit of being told how to build a clock when asked the time of day, I will expound on ThisOldMan's post. The paper (or other material) shim trick to duplicate a worn key is one of the first things taught to apprentices. Interestingly, my first key machine back in 1971 was a cheap Foley Belsaw, with a sewing machine motor and rotary file cutter. It was rather slow, but had a unique feature: The key guide was a vernier micrometer, which allowed one to fine tune the duplicated depth on the blank, and thereby compensate for a known worn key.
Having gone into electronic locks many years ago, I've not bought a new key machine for decades, but I'd like to think these new modern machines that smithies use nowadays, can be programmed to compensate for worn keys. On the other hand, it doesn't get much simpler to slip a shim under the key.
RE. wear.....both lock pins and keys are usually brass, and so wear fairly evenly, but some locks come with nickel silver pins and some key blanks are nickel silver, which is a little more durable. Colored aluminum key blanks were popular once, and they wore down really quickly. Trivia: Over a hundred years ago, Russwin (and Corbin I think) equipped their pin tumbler locks with steel ball bearings under the key pins, theorizing they would rotate as the key was inserted, but in practice, made them more vulnerable to "comb" picks, and so were discontinued in a few decades.
RE lubrication.....like what motor oil to use, many opinions. I'm sure there are recently-invented space-age lubricants that are the cat's meow, but I still use Tri-Flow for exterior locks and graphite for inside locks. We all agree though, that WD40 went out with the Model T.
I've looked at over 40 websites about a storm door not latching and all offered solutions to misaligned latches. [b]This isn't the problem[/b].
When the door was new and latched the handle was perpendicular to the door frame. Now, the handle droops down slightly pulling the latch back into the lock mechanism. This causes the door not to latch. If I pull the handle up so it's perpendicular to the door frame, the latch is full extended until I let go of the handle.
Are there springs inside the lock that pull the handle back up into position after opening the door and releasing the handle? Can I buy those springs or is a whole replacement lock needed?
Thanks!
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