Replacing an Imperial G5007 mortice lock

[LPS]

Hi there

This is my first post here - I am a keen amateur picker, but have no experience fitting locks.

As per the photos below, I would like to replace an Imperial G5007 mortice lock. However, the cost of replacing one of these like-for-like is rather high (£130+) and I would welcome suggestions for a cheaper (but still BS) alternative that would fit, as per the details below. It is a 76mm case with 57mm backset. However, what appears (to my knowledge) to make it unusual is that on the internal side, it is operated by the pictured thumb key and comprises a deadlock only - there is no latch in the upper hole. Thus there is no key hole on the inside of the door, so any replacement lock would need to either be compatible with the current thumb key location, or (unlikely) have an internal key hole at the same location on the inside. Ideally I would get rid of the thumb key and replace with a key hole but this appears unlikely.

From looking online, I am having difficulty identifying a suitable replacement and would be very grateful for any advice in sourcing a replacement.




Many thanks

[1d4]

As you have undoubtedly already found out through your searching, there isn't much standardization or compatibility across makes and models when it comes to dimensions or hole placement. As such, it can be very difficult to find a suitable replacement for a mortise lock, and even more so if price is a factor - mortise locks tend to be expensive. It's no wonder that the tubular lockset became so commonplace. Your best bet might be to repair the one you've got. It looks like it is supposed to have a latch, but that it was removed at some point. A new lock might be expensive, but if you can source a used or broken one, you can salvage it for parts. Also, if you are set on replacing it with something else, keep in mind that the lock that does not have to meet the exact dimensions, if you aren't afraid of removing some wood from the door. Holes can be enlarged or walked over a bit as long as they are hidden by the escutcheon. The mortise itself can be chiseled larger if needed to accept the lock, or made smaller with a piece of hardwood cut to size and pressed in place. Don't be afraid, and good luck!

[rphillips52]

Making a lever lock key-operated from outside but with keyless exit is difficult, hence expensive, hence rare.
These locks are made to order.
https://www.youtube.com/watch?v=aJIfJKk ... e=emb_logo
It is available, eg :
https://www.lockshopdirect.co.uk/produc ... -and-quot-)-39937/
https://www.locksonline.co.uk/Locks/Mor ... dlock.html

However, the function is easily achieved with a cylinder lock. There is no indication of your location, but in some parts of the world, eg USA, cylinder mortice locks are available with screw-in mortice cylinders, or thumbturn on the inside. In Britain, no such lock is now made, they all use a profile cylinder. Profile cylinders in a range of mechanisms, sizes and finishes are available key/thumbturn. Thus one side always needs the key to operate, the thumbturn side only uses the thumbturn to lock/unlock.
Be aware that in addition to the risk of snapping most profile cylinders, a thumbturn cylinder is vulnerable if there is breakable glass, or a letterbox opening, in the door or adjacent. And many thumbturn profile cylinders can be easily opened from the key side by a method of NDE, in addition to the possibility that many pintumbler cylinders are relatively easy to pick or bump.
These problems do not exist with lever locks.

A competent professional locksmith should be able to find you a thumbturn cylinder which is not vulnerable to the NDE method alluded to above — there are now some available.

Finding a lock of exact replacement is generally preferable to the extra work of making something different fit, if the lock is suitable. Otherwise, what is saved on the cost of something cheaper might be spent (in money or time/effort) persuading something else to fit.

[1d4]

A competent professional locksmith should be able to find you a thumbturn cylinder which is not vulnerable to the NDE method alluded to above — there are now some available.

Curious about this. Do you know who manufacters these thumbturns?

[LPS]

Thanks both - your advice is much appreciated.

[rphillips52]

A competent professional locksmith should be able to find you a thumbturn cylinder which is not vulnerable to the NDE method alluded to above — there are now some available.

Curious about this. Do you know who manufacters these thumbturns?

No, I'm not a trading locksmith. When I was working, these methods were not known to burglars. Indeed, profile locks were almost unknown in domestic situations, and just beginning to gain market share for institutional locks.