Hi again,
Before telling you about my progress let me show you a couple of important pictures about the leadscrew and half nut.
As you can see, the thread is not symmetrical. One side is vertical and the other slanted. The vertical side is the "pushing side" so it is very important to put the half nut in its correct orientation.
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This week end I finished the brake. I fabricated a brass piece to hold the spring blade to the part of the arm that remained. Two little 2 mm screws hold it in place and I managed to solder the blade to it. Solder stainless steel with silver tin is a nightmare. You need perfect clean surfaces, very good flux and just the right amount of heat to do it.
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No, I dont like the shiny spring either

I will have to find something more appropriate.
I also started working with the wood case. In some places it has the consistency of a weetabix! I gave it a good dose of woodworm treatment and derusted all the pieces.
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I'm still investigating what kind of wood has been used in this case and hood. Some pieces look like walnut or maybe cherry tree but others are beech for sure. I will need to replace some of the pieces because they are literally falling apart. Its time for start investigating also about how this cases were finished. Maybe they were lacquered or they used some sort of acrylic varnish??