This is more than likely info that many of the members here that have owned tube mods for awhile already know about, but for the new folks that have just purchased a tube mod such as a Caravela that does not have a self-adjusting center pin, or an atomizer like the kayfun Lite that does not have an adjustable center pin in it either ... maybe this can be of some help.
Below is a photo of my Caravela with the 18650 tube. The problem is that it also has a Kick 1 installed in it, and that combined with the 18500 battery, it caused a pretty big gap between the bottom of the tube and the top of the lower cap / fire button assembly when everything was screwed together ... Here is what it looked like once the bottom cap was fully screwed onto the bottom of the tube:
The very first thing you need to make sure is that you have a good connection between the pin on the bottom of your atomizer and pin in the mod's top cap ... Nothing else is important until this happens.
To do this, first screw the top cap onto the atomizer. Once it is tight with no gap between the top cap and the atomizer, then screw the adjustable center pin in the top cap down until it stops. When the pin stops, that is assuring you that you now have a positive connection between the two parts (the 2 pins).
Here is a photo of the top cap and the atomizer. You can see from the arrows where the conection is made between that pin in the top cap and the pin in the atomizer:
The photo below shows what the other end of the top cap looks like (that faces the battery). If you look closely, you can see the hole where the allen wrench goes into in order to adjust the pin as we talked about above. Some pins have a slot cut in them to accept a small flat-tipped screwdriver.
Be advised that once this pin is screwed down to make connection with the pin on the atomizer, this pin still needs to stick out slightly from the plastic insulator (black color in the photo below), so it will make connection with the top of the battery, or the brass connector on the Kick module (if you are using one):
Here is that brass connector on top of the Kick module that the pin in the tube's top cap needs to make contact with (same thing with a battery if your not using a Kick).
Now for the problem ... Once you have your tube's top cap and atomizer installed, you now install the battery from the bottom, and then screw down the bottom cap onto the tube. Once the bottom cap is installed, you can shake it to see if the battery rattles around inside. If it does, it wont make a good electrical connection. All you can do at this point is get a longer pin from Lowes or Home Depot and cut it to the correct length in order to not only make that correct connection between the atomizer and the top cap (as we described above), but to make a good connection for the battery.
But ... This thread was written to address the problem of a gap between the bottom cap and the bottom of the tube.
You now have 2 choices if you want to eliminate this gap:
1. The recommended way to eliminate the gap is to make the pin in the top cap shorter. This will decrease the gap between the bottom cap and the tube when the bottom cap is tightened down. Just remember; You can only make this pin so short ... Make it too short, and it won't make a good connection to the top of the battery (or the Kick if your using that) ... Remember, it has to stick out of that black colored plastic insulator slightly.
2. Once you make the top cap pin as short as you can (and still get a good connection), there is nothing else you can do but follow these instructions ....
If you look at the flat surface of the bottom cap (as indicated by the arrow on the photo below), you can grind that surface down a certain amount. This will allow the cap to screw into the tube farther before it makes contact with the bottom edge of the battery ... This will get rid of that gap.
The photo below shows my bottom cap that has been ground down using a little stone grinding attachment on a Dremel tool. After grinding, I sanding it across a piece of 80 grit sandpaper to insure it was smooth and flat, then against a piece of 800 grit wet / dry sandpaper which was wetted with oil ... Then when I was done, it was polished with Mother's Mag and Aluminum polish.
The bottom cap on mine is made from brass and grinds down very quickly.
Again, here is the cap after being ground down (there were 2 grooves in this cap that are now gone since I ground it down):
Now .... No gap!
That's it ..... Hope this may be of some help to somebody
Below is a photo of my Caravela with the 18650 tube. The problem is that it also has a Kick 1 installed in it, and that combined with the 18500 battery, it caused a pretty big gap between the bottom of the tube and the top of the lower cap / fire button assembly when everything was screwed together ... Here is what it looked like once the bottom cap was fully screwed onto the bottom of the tube:
The very first thing you need to make sure is that you have a good connection between the pin on the bottom of your atomizer and pin in the mod's top cap ... Nothing else is important until this happens.
To do this, first screw the top cap onto the atomizer. Once it is tight with no gap between the top cap and the atomizer, then screw the adjustable center pin in the top cap down until it stops. When the pin stops, that is assuring you that you now have a positive connection between the two parts (the 2 pins).
Here is a photo of the top cap and the atomizer. You can see from the arrows where the conection is made between that pin in the top cap and the pin in the atomizer:
The photo below shows what the other end of the top cap looks like (that faces the battery). If you look closely, you can see the hole where the allen wrench goes into in order to adjust the pin as we talked about above. Some pins have a slot cut in them to accept a small flat-tipped screwdriver.
Be advised that once this pin is screwed down to make connection with the pin on the atomizer, this pin still needs to stick out slightly from the plastic insulator (black color in the photo below), so it will make connection with the top of the battery, or the brass connector on the Kick module (if you are using one):
Here is that brass connector on top of the Kick module that the pin in the tube's top cap needs to make contact with (same thing with a battery if your not using a Kick).
Now for the problem ... Once you have your tube's top cap and atomizer installed, you now install the battery from the bottom, and then screw down the bottom cap onto the tube. Once the bottom cap is installed, you can shake it to see if the battery rattles around inside. If it does, it wont make a good electrical connection. All you can do at this point is get a longer pin from Lowes or Home Depot and cut it to the correct length in order to not only make that correct connection between the atomizer and the top cap (as we described above), but to make a good connection for the battery.
But ... This thread was written to address the problem of a gap between the bottom cap and the bottom of the tube.
You now have 2 choices if you want to eliminate this gap:
1. The recommended way to eliminate the gap is to make the pin in the top cap shorter. This will decrease the gap between the bottom cap and the tube when the bottom cap is tightened down. Just remember; You can only make this pin so short ... Make it too short, and it won't make a good connection to the top of the battery (or the Kick if your using that) ... Remember, it has to stick out of that black colored plastic insulator slightly.
2. Once you make the top cap pin as short as you can (and still get a good connection), there is nothing else you can do but follow these instructions ....
If you look at the flat surface of the bottom cap (as indicated by the arrow on the photo below), you can grind that surface down a certain amount. This will allow the cap to screw into the tube farther before it makes contact with the bottom edge of the battery ... This will get rid of that gap.
The photo below shows my bottom cap that has been ground down using a little stone grinding attachment on a Dremel tool. After grinding, I sanding it across a piece of 80 grit sandpaper to insure it was smooth and flat, then against a piece of 800 grit wet / dry sandpaper which was wetted with oil ... Then when I was done, it was polished with Mother's Mag and Aluminum polish.
The bottom cap on mine is made from brass and grinds down very quickly.
Again, here is the cap after being ground down (there were 2 grooves in this cap that are now gone since I ground it down):
Now .... No gap!
That's it ..... Hope this may be of some help to somebody
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