Unfortunately, even with high-end stuff things can go wrong without a cautious and watchful eye.
With a high-end mechanical like the Caravela, there is no insulator where the battery rests on the switch assembly. If your battery wrapper is compromised, or doesn't wrap around enough, it's going to short if it get's nudged a bit to the side. There's a type of Panasonic battery out there that does this, where the diameter of the exposed negative side of the battery is too large.
A good amount of the posts on high-end rda's are still merely press fit into the deck somehow. The exact same thing can go wrong. They can turn or wobble.
People love phillips head screws instead of the hollow tiny Hex-key ones, but those phillips head screw posts can't tighten down as good on the wire, sometimes coming loose, and the larger heads can contact each other (in your case), or they add more height to the posts, brining in the potential for a metal drip tip that goes a bit deeper into the chamber to make contact. (happened to me once)
You have to be aware of the "little things" that can go wrong with a mechanical. As soon as you take a regulated circuit or fuse out of the equation, it's all up to the user's watchful eye and cautionary execution to use them safely.
With a high-end mechanical like the Caravela, there is no insulator where the battery rests on the switch assembly. If your battery wrapper is compromised, or doesn't wrap around enough, it's going to short if it get's nudged a bit to the side. There's a type of Panasonic battery out there that does this, where the diameter of the exposed negative side of the battery is too large.
A good amount of the posts on high-end rda's are still merely press fit into the deck somehow. The exact same thing can go wrong. They can turn or wobble.
People love phillips head screws instead of the hollow tiny Hex-key ones, but those phillips head screw posts can't tighten down as good on the wire, sometimes coming loose, and the larger heads can contact each other (in your case), or they add more height to the posts, brining in the potential for a metal drip tip that goes a bit deeper into the chamber to make contact. (happened to me once)
You have to be aware of the "little things" that can go wrong with a mechanical. As soon as you take a regulated circuit or fuse out of the equation, it's all up to the user's watchful eye and cautionary execution to use them safely.