Framing For Support Box

[turbocruiser]

The support box is open on top. Here is a link to a similar support box-

http://woodheatstoves.com/6-x-11-ceiling-support-p-188.html

The image shows the bottom of the box where the interior pipe would attach. The other end is completely open, allowing you to screw or nail to the wood supports from the inside. You want to keep all attic insulation away from the pipe and the inside of the support box by using an attic insulation shield or a support box long enough to go all the way to the roof if you're installing the chimney on the low end of a scissor truss.

Wow, again a picture is worth a thousand words and a video is worth even more! Thanks that totally clarifies a few things for me. I've assumed all along that the Inner Diameter of the support box matched the ID of the chimney pipe and stove pipe. I therefore also assumed that the support box itself was in the exhaust flow from the stove.

Because of those two incorrect assumptions I assumed the only way to secure the box to the framing was from the outside to the inside with screws that would penetrate the support box but not the tube on its inside.

Then I read of people screwing from the inside to the outside and started thinking that the support box must be open on the inside but that would lead to all sortsa awful things.

I guess the right way to think of this one is that the support box IS open on the inside but also that the support box itself isn't really a part of the exhaust flow from the stove at all ... it simply supports the chimney, maintains the correct clearances and completes the ceiling transition. Is that right? Then as far as exhaust path, that goes strictly from stove to stove pipe to chimney pipe and technically the support box isn't involved at all. Is this all more or less right?

Thanks again for taking the time to help me through these basics everyone, I really appreciate it.