Woodworking, household

Wooden door latch

A little while ago I was browsing the web, and I found an interesting site, that contained a number of wood working projects. Amongst the site I found this:

http://woodgears.ca/wood_hardware/doorknobs.html

I thought the door latches looked really nice and I was inspired. I have been getting slowly more annoyed with my bathroom door, as the lock mechanism isn't aligned properly any more and was difficult to use. I could have just fixed that, but then I'm not a massive fan of the brass handles used throughout my house either. So I decided I'd try my hand at making a door latch mechanism inspired by those I'd seen.

This has turned out to be a rather lengthy little project. The material I had to hand was some 2x4 American white oak. I had bought this originally hoping to make a large mirror frame for my brother. However I realised that I was unable to achieve the profile he wanted (without the use of a spindle moulder!)

Whilst this is a nice material for such a task, 2x4 is not really the right size to start. And I don't have a bandsaw (yet, but xmas isn't far now) So this has involved a lot of manual sawing.

And sanding and shaping, and just generally a lot of steps.

The latches have quite a lot of parts once you break it down.

On the inside there is a backplate, a main body, a latch, a knob for one end of the latch, a hook for the latch to hold into, a locking pin to restrain the latch from moving up, and the main pin running through the door. The other side fortunately just has a back plate, a door handle and knob for the end.

door handle
door handle
Main body and backplate
Main body and backplate
door knob
door knob

So that's an interesting combination of regular wood working, and a few turned items. I chose to make all the turned pieces from some oak kindly given to me by a colleague last year. Which is now reasonably dry.

This means that there is a slight contrast of colour, in two varieties of oak.

One of the interesting challenges has been to figure out the spring return mechansim mentioned on the website. The main problem being, what kind of spring? From where? Initially I attempted to make a mechasnism as described, but the only spring I could lay my hands on came from a pen. I did try looking around some hardware stores but I didn't find anything more suitable.

So I drilled a recess hole fo the spring, and turned a small wooden piece to go on the end, and all together it looked quite promising. However it seemed that the mechanism might be quite prone to sticking, probably the angle of the hole wasn't steep enough. Also After a short while I realised that whilst the spring was enough to hold the latch in place when on its own in the body of the handle. Once it was held against the backplate, and there was a little more friction, the spring was simply not strong enough to have any sensible effect.

I briefly considered leaving it without the spring return mechanism. But knew that I would get annoyed with it if it just flopped about.

Back to the drawing board...I spent a while wandering around, trying to think of sources of springs that might work. Racking my brain, working through everything I own considering if there are springs. I knew I had an old router that had some springs, but they were even weaker than the pen. Eventually my brain started to have a vague recollection of a shape of spring. It's hard to explain how strangely human memory works sometimes. I literally felt the form of a remembered spring type slowly come together, as I groped for the memory of where I'd seen such a thing.

Then suddenly I realised... Clothes pegs. Of course! They have powerful springs, but they are primed to close not open. Regardless I rushed outside to grab a peg, and rip out the spring. Whilst it is normally geared to close, I found it relatively easy to bend it back such that it's default state was an open position, and it resisted being closed. What's more it's about the perfect width for my latch.

The pegs I had were rather rusty, so I actually bought another whole pack of wooden pegs, and retrieved a nice new spring.

This meant a slight change in design, I needed to drill a small recess for the body of the spring to sit just beneath the latch, in the body.

From this position the spring provides lots of resistance. It's perfect.

pb150068
pb150068

Well, it was perfect, right up to the point I actually attached it to the door with all the pieces in place. Unfortunately the friction of all the pieces together is still too much for the spring to counter. It's possible that over time and use, the friction will lessen and the spring will come into effect.

Another problem I've noticed since putting things in place is that the small screws I intended to use to hold the handles onto the shaft, are just not up to the forces. I have upgraded one side to a longer screw that passes all the way through the shaft. And will need to update the other side also.

The last thing to do will be to make up a retaining piece for the door frame. This should be relatively simple. Though the nature of my door frame means I can't easily make a retaining catch like the one in the above website.

The main latch
The main latch

Update, obviously from pictures below I finished making the retaining piece.

external handle
external handle

I guess as projects go, I'm relatively happy with how the thing looks, but I'm not so happy about how it's gone. It's been a lot more fiddle than I anticipated. And a few things have required revision on the fly, as I found things weren't working and had to come up with a plan B.

So I guess it's been a good learning experience, there are just some things you have to find out when you try them. I guess I could of gone for a much more simple latch mechanism and avoided most of the hassles I've had. But part of the challenge was to make something pretty close to the pictures I'd seen.

It gave me an opportunity to try out the drum sander kit I won in the HWA raffle a few months ago, and of course turning the handles and pivot pins etc, was good fun.

But for me it's back to just wood turning for a bit. I've had my fill of mechanisms for the moment.</p>

Update: 19th November, Today for the first time I noticed the spring doing it's job and pushing the latch back to horizontal. I guess it's worn in enough that the friction is nolonger greater than the force of the spring...yay!