I recently fully serviced this Seiko 6309-7049 vintage diver for a ClockSavant customer. This watch is now performing superbly with excellent performance, similar to or better than when it left the factory years ago. It is also now water resistance and passed the swimming test of 100 meters though I recommend against swimming in vintage watches. I wanted to note a few things with this particular post. First, take a look at how dirty the case is. There’s also corrosion. The time it takes to clean this case, remove corrosion, and then achieve water resistance is substantial. It’s another example of the difference between quality servicing and skipping steps, and the watch looks and feels like it’s reborn after you get rid of this dirt to include the dirt you can’t see. I’ve shown pictures of dirty mainsprings, I wanted to show what a properly cleaned one looks like. In the picture where I am holding-up what looks like a pin vise with a part in it, this is a specialized tool called a mainspring barrel arbor holder. This is designed to hold, without marring, the mainspring barrel arbor— the part in the middle of the mainspring barrel that holds the mainspring and through which power is built and held. This is another in a long list of specialized tools used to deliver the best possible results.