Removing broken mortice lock

[Dave Baker]

The mortice lock in the front door has just decided to freeze in the locked position. The mortice moves with the key about 2mm and then goes solid so I guess something must be broken in the lock mechanism.

There's just enough gap to get a hacksaw blade in to the mortice but it's pretty slow going and I think there are steel bars inside the bronze because I've already hit something the blade doesn't seem to want to go through. Getting an angle grinder in would bugger the door and frame unless there are such things as cutting disks no more than a mm or so thick. Mine are at least 1/8".

Any bright ideas short of ripping half the door frame out?

[Dave Baker]

Ha! Might just have answered my own question on the Googles.

thick metal cutting discs to fit most angle grinders.

[Ash]

Try

?productId=70545

[The Medway Handyman]

SF do 1mm cutting discs

you get to the hinges? Sometimes you can knock/drill/cut out the pin. Failing that, get a pry bar into the gap & use the AG.

[Roger Mills]

What sort of door/lock is it? Is is also a latch, with handles and plates either side? If so, can you see any of the guts if you remove the handles and plates?

I recently had exactly these symptoms with a Eurolock-based latch/lock mechanism in an aluminium door between my house and conservatory. A bit had broken inside the lock which meant that turning the key no longer lifted the interlocks out of the way of the bolt, with the result that the bolt couldn't move more than a mm or so. By removing the handles and plates, I was able to poke around with a screwdriver and lift the offending interlock manually - enabling the key to unlock the bolt.

[If it's of any interest, the whole thing is covered in a thread "Any lock experts out there?" which I started back in April/May this year].

[Frank Erskine]

On Wed, 14 Oct 2009 22:01:29 +0100, "Dave Baker" had this to say:

If you _could_ get a 1/25" cutting disk for an angle grinder it would be so fragile that you'd have to use some sort of a jig to guide it without any twisting.

WD-40 would seem to be the answer to all your prayers, if you can believe a few posters in here....

It's not a Yale lock, is it (lubricated with the above as recommended by Yale)?

[The Medway Handyman]

It wouldn't have jammed had it been lubricated according to the manufacturers instructions e.g. with WD40.

[Andy Dingley]

"Stainless steel cutting disks" (Screwfix, and Aldi, et al)

Extra thin, bit brittle and the wear rate is high, but they're great for mortice bolts.

[Dave Baker]

First thing I tried but all that's behind the plates is a little hole in the wood for the key to go through and then the keyhole in the lock itself. Nothing further to dismantle unfortunately. A thin grinding disk seems to be the way to go now I know they exist. Should be a piece of cake once I get some to fit my grinder.

[R]

> 1.2mm thick metal cutting discs to fit most angle grinders.

Got around 50 in the back of my van for a 5" AG. Cut like lasers they do

[dom]

The locksmith's method I've seen is to drill through the door, into the lock body, at the right point (say a 6mm hole) to lift the tumblers with a wire or thin screwdriver, and then to use a timber plug or dowel to patch the hole.

You would need to dismantle an identical lock to figure out where to drill.

[Thomas Prufer]

... and the thinnest are 0.8 mm.

You may want to scrounge around for a very worn disc as a shim and support -- the thin discs come with a bit cardboard, but an old disc is better.

Thomas Prufer

[Dave Baker]

The handle plates are pretty big, 2" wide or so and I'm now thinking I could chisel out the wood under one side to about 1" wide behind where the mortice goes, get in there with my cylinder head porting gear and carbide burrs and rip the lock open and just destroy everything behind the mortice until the lock's an empty shell. Once the plate's back on it'll all be hidden. Might take a while but given I have this gear and not the cutting discs it sounds like a plan.