Sunday, January 4, 2015

And the lock is finished!

In the last blog I finished the key mechanism, now it was time for the bolt. I had a somewhat thicker piece of steel, 1/4" thick from an old bracket. Cut it with the hacksaw (took some time!), then cleaned it up with files. Making the actuation gate for the key was done with hacksaw, angle grinder and files. It's easy to cut into a piece of steel with a hacksaw, but not so easy to turn a corner. I could use a turning saw with metal cutting blades, but blasting away the metal with the angle grinder is much quicker! Finishing down to the marking lines is a job for the files again.

The two ports for the bolt were made similarly with the same tools, this time from 4mm flat steel. The pins for rivetting are still too long in this picture.

I took my time to locate the positon of the ports and the holes carefully. Easy to make a stupid mistake here. Rivetting needs to be done with care. It's not a matter of squashing down the metal with mighty blows. You use the fin of the hammer to drive the steel into the countersink, working around the pin. The rivet shouldn't be too long, or it just bends over, or too short and it never fills the countersink. You need some practice. A good job means that you can almost make them disapear in the surface when you file them flat. I still need a lot of practice then...

This shows the mechanism with the key pushing the bolt into the closed position. I welded some blobs on top of the bolt and filed these so they act as a stop, preventing the bolt from ever falling out of the lock. I also added a leaf spring to put some tension on the bolt. You can also see that I am only a very average mechanic, but all this is going to live inside the door style. Most important, the lock works very smoothly.

And this is the front view.

And here is my little metal working corner. A sturdy vise. Hacksaw and a lot of files, I like the Bahco files. A drill press, and the Mig welder. When you are inspired to give it a try, but you don't have a welding rig, I think you could do a lot with rivetting and some silver soldering too. I am not quite sure about the key, but there probably is a different assembly method for that one too.

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