Help - Diver Extension loose on Titanium Seamaster Professional 300

The dive extension does not usually rely on the pin you are referencing to stay shut. In a steel clasp, the extension has two small areas that have been flattened under a press to create the friction - see the red arrows:



On a steel clasp there are two ways of fixing this. One is to try to open up the two forks of that area of the clasp, but that can only do so much. I often end up using a punch in a staking set to spread those two dimples out more to tighten up the dive extension:



Just flattening those two small spot out can take an extension from falling open every time you take the watch off, to making it tight enough you have to really work to get it open, or anywhere in between.

On the Ti clasps that I have paid attention to, they use a very different system. Instead of having spots where the metal has been deformed, they have had one small spring loaded part built into this area that looks like this:



This is the inside of the clasp pictured, and you can see the clasp number (SMP Chronograph bracelet) and you can see the small spring loaded tab just sticking out on the bottom half of the extension fork:



The other side doesn't have one, so I'm not sure if your clasp is showing the side that is supposed to have the spring loaded parts, or the other side. I can't make out from your photo what is really going on in that spot, so if you could take a better photos that would help, but I would suggest looking at the extension to see if it has this small spring loaded part on one side or another.

If it does, and it still seems to work properly (you can push it in and it pops back out, and doesn't look terribly worn) then you may be able to tighten it up by spreading the two forks of this area of the clasp, in particular if they seem to narrow where they meet the bracelet. It may help make better contact to keep this locked in place.

Let us know what you find.

Cheers, Al

Is there any friction between the surfaces I've shown with red arrows?

Not asking if they are smooth - what I'm asking is if there is any friction between these surfaces when you are tucking the extension in place.

If there isn't, then it's unclear what is supposed to provide the friction to keep the extension from simply opening.

Is there any evidence of wear at the red arrows I've added?

Sorry, I can't tell as much from a photo as you can looking at it directly. If you are implying that it is worn, then no I'm not going to tell you to buy a clasp immediately. If this "clipping" over the tube is what is supposed to hold this closed, is a piss poor design frankly.

But before you get a new clasp, if you can bend this part, you may be able to restore friction by creating more interference between the tube and this slot. Unclear which way to bend it at this time, but my gut tells me you should put more curve in it, so bend it in the direction it is already curved, and see of that helps. This is sort of the same idea as the old flimsy Rolex claps...