Fitting lock on to old fashioned mortise doorknob

[b3ff]

First of all, I apologise for my lack of information/bad explanation. My knowledge of door handles and locks is extremely limited!

I have old fashioned doorknobs in my house, where the latch and lock are inside a box which is attached to the outside of the door like this: http://i.imgur.com/oV6NuP7.jpg

Here is the inside of the box: http://i.imgur.com/t34Waci.jpg

I don't have a key, if I took it to a locksmith would I be able to get a key, are all the parts there?

 

[Burnerman]

Thats an ancient cast rim lock......it seems to be complete, and the catch part will certainly work. The lugs that operate that part of the mechanism are still there.
For knobs (if you need to replace) look at Toolstation 48201.
If you can find a long established lock smith, he may well sort you out with a key - very basic security, here - but it'll be from his odds and ends box.
John

 

[JohnD]

That is a very old lock, you are looking at pre-Victorian antiques here. It might be from a midlands maker, or it may be from a local country workshop*. It appears to be a simple tumbler lock with no levers. I can't see any wards, though there might be some on the other part of the case. You may find a hobby lock enthusiast willing to help.

Try
http://www.antique-locks.com/forum.php?s=e95afa9a1010d5d160679a070ceeacbe
where they will be interested in what you have. I am an infrequent member. There are no references to Bromhead on the site. You could ask for a key on http://www.antique-locks.com/forumdisplay.php/12-For-Sale-Wanted but the chances are someone will have to file it up for you.

Do not imagine that your old lock will give you any security, you would need to attach a modern, smaller lock to the door for that.

Your old lock is valuable for its originality and authenticity in a (presumably) very old house, it would be vandalism to remove or alter it.

* edit: I see from the cartouche that is marked Bromhead of Bristol. However there is a chance that this is the retailer, not the manufacturer.

I see a reference to "Bromhead & Son, iron mongers & kitchen range manufacturer" in Milk Street, Bristol, in Mathews' Bristol Street Directory 1871
https://www.flickr.com/photos/brizzlebornandbred/11468138106/?rb=1

 

[gregers]

take a look at your local antique shops and have a rummage through there old keys,im sure your find 1 to fit.
or your local locksmith,it looks like a bog standard old key so shouldnt be too hard to make 1 up.