Mortice lock getting trickier to open from outside

[PeteMP]

I have an issue with the mortice lock on the door of my flat that's in a communal building (3 other flats) - it locks and unlocks fine from the inside, and locks fine too from the outside. However, over the last few days, unlocking it from the outside is getting trickier - if it seems to be stuck, giving it a quicker turn with a bit more force behind the turn budges it. I've not been locking it just in case when I go out, which of course isn't ideal - is there anything straightforward I can try (WD40 etc.)? I am one of the least DIY minded people ever so anything involving drilling or taking the lock out is beyond me!

 

[JohnD]

There are lots of locks. Please show us some photos of yours.

Perhaps it is dirty or worn out.



Also, try using the key when the door is open. Is it any easier?

 

[JohnD]

Include photos of the bolt of the lock when it is out, from both sides, above, and most importantly from below.

And of the staple (keep) in the doorframe.

And a photo of the key. It may have worn bits. Try your spare key and see if it is the same.

 

[PeteMP]

Right, the spare key works fine, having tried it a good few times, though it didn't latch on perfectly one time - guess that's just how spare cut keys go? (Told you I was ignorant about all of this). I can see the top edge of the original Chubb key having been worn down, as you can see in the pictures (please excuse the door that could do with a good clean - thought I'd attach those lock photos anyway).

I guess I'm fine then regarding the lock being OK? Should I get another key cut or can I get a replacement for the original?

 

[JohnD]

Key is badly worn. Those rounded bits should be cut to a sharp square.

In most cases key cutters will just copy whatever you take in, so copy your best, least worn key, get a couple of spares, keep the original for "best"

The actual cut depth can be looked up from a table, and the keys cut to measurement, but that would not be economic.

I think your lock is a Chubb 3G114. You can still get them, though the 3G114E is the improved version, and now sold (by the same company) under the Union brand name. It will fit into the door as a straight replacement, though the bolt is slightly larger so you might need to shave out the doorframe a fraction.

Look at the price before spending much money on new keys.

I could probably sell you a serviced used one if times are hard.

 

[PeteMP]

I usually get them cut at Timpsons (most reliable keycutter near me) and that spare is the best.

So ultimately, no new lock needed, just a case of a worn key?

Thanks for all of your advice by the way.

 

[Alec_t]

Perhaps the lock itself could benefit from (graphite) lubrication if it is getting stiff and causing accelerated wear on the keys.