Patio Door lock stuck in locked position

[ellal]

Got a wooden patio double door which has top and bottom locks on the secondary door.
The key in the bottom one is just spinning and not unlocking.

Not sure what you call this type of key, but it operates the lock.
Any ideas as to whether there is anything I can do, or is it a locksmith job?

 

[chirpychippy]

The Key is a Star Bolt Key, try buying a new one before employing a lock smith. Try jiggling the door as your turn the key or lift the key up and down, side to side to engage it with the splines.

Also you can take the cover plate off and see if you can see the splines of the lock through the little hole, the hole in the timber should be about 10mm wide, you could spray wd40 into the hole and into the lock aswell.

 

[JohnD]

See if you can reach the bolt with a thin knife blade or similar. You may be able to push it back.

There is a notched lever inside the tube that is supposed to wedge into the teeth of the bolt to prevent it being pushed back. With a horizontal bolt, when you push the key in, it pushes this lever up so the bolt can slide in and out. You can also lift the lever with a very small screwdriver or other small tool.

If the bolt has been fitted upside down, you push the lever downwards to release it.

You might possibly be able to see teeth and lever through the keyhole. If you can lay your hands on a spare bolt you will see how the mechanism works

The usual cause of failure is the splines on the key wearing out so they no longer reach the teeth on the bolt. But your key does not look worn. Perhaps a tooth has broken on the bolt. If the spring is broken or jammed the bolt may have rotated, or pushed too far, so the key can't reach the teeth. As it is the bottom bolt that has failed, it may have dropped too far by gravity, perhaps because the retaining spring lever is broken. If you can push it up a bit, the key may be able to grip the teeth. If you can't push it up, you could saw through it.

The mechanism is very simple so there is hardly anything to go wrong except the spring lever or the teeth.

 

[ellal]

Thanks for the replies.

I'll try having a look, and give the magic spray a go.

It was working fine, and then all of a sudden the key went slack (no click) and will now only turn continuously in either direction.

 

[ellal]

Had a look and compared top and bottom locks.

The top lock has a notch on one side and a small piece of metal which I'm assuming is the spring.

The bottom lock has neither, just a round hole..

 

[JohnD]

The spring might have fallen out of place, allowing the bolt to drop.

Try the thin knife trick

On the older ones, the bolt is made of brass so fairly easy to saw through if you can get a blade under the door.

 

[chirpychippy]

The spring might have fallen out of place, allowing the bolt to drop.

Try the thin knife trick

On the older ones, the bolt is made of brass so fairly easy to saw through if you can get a blade under the door.

View attachment 376952

If you do saw through the bolt leave the saw in place and open the door, otherwise the bolt may drop again and you'll be back in the same boat.

 

[ellal]

The spring might have fallen out of place, allowing the bolt to drop.

Try the thin knife trick

On the older ones, the bolt is made of brass so fairly easy to saw through if you can get a blade under the door.

View attachment 376952

Unfortunately I can't check the top one, so can't ascertain the metal type.

I reckon I can just about get a multi tool blade in the gap under the door.

If it's brass it should go through?

 

[JohnD]

Yes, though I find the blades wear down quite quickly.

You might also be able to use a hacksaw blade

 

[ellal]

Angle not there for a hacksaw blade unfortunately