I am very sorry to read of your loss. I have a good friend who was recently widowed and she is finding it quite bewildering.

When you say you cannot lock your door is that because you don't have a key, or because the deadbolt has no hole to receive it in the jamb?

A new key can be procured by taking the lock (out of the door) to a locksmith. Or even just buying a few bit key examples and seeing which one fits. Which highlights the lack of security of that style of lock and an old-fashioned bit key. I have to confess mine are just like it, but we don't live in a particularly dangerous area.

If the problem is that there is no pocket in the jamb to recieve the tongue (not sure the technical term for the part that will stick out when the deadbolt key is turned), then the solution is to have a carpenter create the hole and attach a plate to reinforce it. It's a simple job.

If the problem is that you have the key, and that there is the appropriate hole in jamb but that the key won't turn in the lock, it just needs to be cleaned. You could try some WD40, but it may need to be removed from the door and cleaned. This is not hard to do. Just take pictures as you go, and perhaps put every little piece in a separate, and sequentially numbered, yogurt cup (or similar container) as you go, so you know how to retrace your steps on reassembly.

Or the problem maybe that you want a more secure lock (which wouldn't damage your door, no matter how historic it is), then I would find a qualified locksmith and get it done. Medeco locks, I believe, are very well-thought of (and a higher-cost) brand. You may or may not have enough thickness to the door for such a lock. Other good brands would be Schlage, Baldwin, etc. Some of these have mid-to-lower cost lines for sale at Home Depot or Lowes.

Installing a lock like this requires hollowing out a pocket for it within the door. It can be a tricky thing to do on your first attempts. If you can afford it, it's something I would have a pro do. It's not hard or involved, it just takes experience and special tools, so it wouldn't be ruinously expensive.

As to whether you should replace the hardware, that depends on whether you could find newer ones that fit in the pockets. I would start with cleaning, making sure the deadbolt/key thing is workable and then consider adding another good-quality deadbolt to the door. If you are particularly worried, you might need to reinforce the jamb, as well.

I am suggestig these smaller steps at first because I (as an older woman) find it comforting to take on stuff and fix it myself. It really adds to my underlying sense of security.

I hope my answers help you.

Liriodendron

Lincnkel, you don't need to replace the hardware, or necessarily even remove it. A hardware store sells a selection of skeleton keys, usually about $1.00 each, just buy one of each and see which one fits and turns the lock. If it sticks, use WD40 on it, and let it do its thing for a bit--you may have to tap on the bolt a bit to free it.

My house built in 1908 has such a lock on every door, inside and out, and I have found keys to fit with no problem. Some I had to lubricate to loosen, but I didn't have to take any out. Since it has that style of lock and bolt, I am sure there are the appropriate holes in the jamb to receive them. If not, you can get a plate at the store to install, and drill out some holes with a bit and a chisel to make them fit. No locksmith or carpenter required.

My front door also has a 'night latch' which operates with a key on the outside, and a knob on the inner side--it's installed above the main lock about a foot or so. You can purchase one at Lowes or a hardware store, usually around $20--you will need to drill a hole in the door for the lock cylinder, and attach the matching lock plate on the jamb side, but instructions are included, so it is a diy job also.

By the way, that looks like bronze egg-and-dart hardware in great shape--mine have a full backplate rather than just a key escutcheon...but if you want to discard it--I'll gladly take it!

I live in a university area, my front door has a full length bevel glass light in it--and in 25 years, I've only been broken into once--and they came in through the kitchen window on the side, and left out the back door. I knew this when I got home that afternoon because my cat was waiting for me on the front porch--a friend had taught her how to open the screen door in back! :)

Hope this helps!

It looks like you have a mortise lock set with warded keys.

A 'skeleton key' is a warded key with all the wards cut away so it can work in any warded lock (or at lest many).

The upper slopped item is called a latch, the lower square item (pulled into the lock) is called a bolt.

Latches allow the door to be held closed after just pushing it closed. The sloped shape pushes them into the lock and then they spring back out when the door is fully closed.
The bolt is often a 'thumb' operated knob on the inside to lock the door.

Both can be placed out to lock the door more securely.

The buttons on the lock select lock on closing mode or 'no' lock on closing for the latch.
The key will operate just the square bolt, and usually locks the knob also (both the latch and the bolt then are locked outwards to secure the door).

If there is no key on the outside the lock is not all that bad.
Once the latch is locked you have to break the jamb or the door to gain access.

The outside key is often the main weakness.

If you have another door to gain access when this one is locked you just need to get a key (and a 'skeleton' key can work here) so you can throw the bolt.

If you want you can replace the whole lock and add an exterior modern key cylinder to operate the new lock from outside.
Most have a knob on the inside to operate the bolt.

You could do what was done to my front door. Add a deadbolt lock to the door and just use the original knob for opening and closing the door.

This might be your problem. See the 2 buttons on the side of the door with the bottom one sticking out in your 2nd picture? The door is in the unlock mode. Push the lower button in all the way and the top button pops out. Now the outside door is locked and you need a key to open it.

Please please if you can possibly handle it--do NOT let a locksmith talk you into a cheap tube lock and drill a nearly 3" diameter hole in your antique door. That was done to my house by a previous owner--the agony!

I realize you are going through a difficult time but I'm just mentioning this so you don't fall for bad advice or a cheap fix. Stick to mortise locks. There are plenty of modern ones available. We were eventually able to repair our door and get a mortise lock installed. They can be pricier than tube locks, but we got the "guts" on ebay for a fraction of retail, and then just ordered the handle (making sure it was the same mfg. and compatible) from our locksmith.

Best of luck with your door. I hope you can get the original lock working the way you need it to, but if not, avoid the tubes :-)

Buy a surface deadbolt. They require a 1.5" hole. A regular tubular deadbolt, which are stronger and more modern, needs a 2 1/8" hole. Don't know where the alleged 3" hole comes from. You apparently have a 1 3/8" thick door, which for an exterior door is not really desirable. The existing lock will not provide much security even if you could get both keys made for it.
Casey

Here is a link that might be useful: surface deadbolt