More mortice lock questions

[Dave Baker]

Following on from my earlier thread I've hopefully got a mate sending me some 1.2mm thick cutoff discs for my angle grinder soon so I can cut through the jammed mortice. After that am I likely to be able to find an identical sized lock to replace this 25 y/o one of unknown origin or is more carpentry likely to be needed? I have no idea if locks have some sort of standardised range of sizes or if every manufacturer does their own thing.

It would be ideal to get one that just slots straight back into the same hole in the door.

[Dave Osborne]

It's probably a standard size. What brand is it?

[Roger Mills]

It will be a "standard" size - but there are *lots* of standards - so you need to measure all the dimensions - length, width, offsets, etc. and find another one the same.

Does yours look anything like this?

[Dave Baker]

If I could get it out I could maybe tell you but at present "unknown origin" is my best guess.

[Dave Baker]

has only 3 prongs on it though and I've just had a measure and it's exactly

45mm from the edge of the door to the centre of the keyhole. So it's looking like a standard 67mm lock then? Every dimension will be the same in a new lock?

[Dave Osborne]

OK, best to take it to the shop when you do finally get it out and compare directly with potential replacements. If it is a well known brand, you should consider starting with that brand.

If you want to upgrade to a higher spec., e.g. Chubb BS3621 Insurance Approved, then you should be aware that Chubb do the 3K74 and the 3U74, which are notionally identical apart from the fact that the 3U74 case is sized to replace "standard" Union/Yale locks and copies thereof.

[Geo]

Union 3-lever lock dimensions on this page. (Note that 3 lever locks are fairly easy to pick)

or shorter:-

[The Medway Handyman]

I'm fortunate in having a large speciality lock shop quite near. When I replace locks I always take the old one there & so far they have always been able to supply an exact match.

[NT]

NT

[Derek Geldard]

IME Often the new lock is a standard-ish size but the box staple (?) (the bit the bolt locks into) isn't.

Derek

[Roger Mills]

That's a good start, but there are other dimensions which might vary - like the vertical distance between keyhole and latch. They're all shown in the link posted by 'Geo'.

[fred]

In article , Roger Mills writes

I think the strike side will almost certainly need opening up, the deadbolt width increased a bit with the 2004 revision of BS3621 so things had to move to accommodate it. At least the strike side is the easier one to modify. The strike box will be deeper to take the longer throw too.