coaledsweat wrote:If you have about 4-6" of extra stovepipe laying around, Hammer flat or snip the seam out of it and wrap it on the end going into the stove with the split side opposite the stovepipes seam. Hopefully it will fit snugly into the stoves collar and you can secure the sleeve to the stovepipe with two screws. If you stick 3" of stovepipe in, you should have about 3" more sticking out for those screws. Secure the stovepipe with 3 screws to the stove (always 3). A wipe of sillycone or stove cement and your set. It should come right out and go back in when you service it. If the gap is real big, cut your stove pipe lengthwise and roll it up like a paper towel roll around the stovepipe. Wear gloves, that stuff is sharp.
I recommend installing the pipe as Coaledsweat advised. If there are no holes you can drill them, even if it's cast iron. The pipe is supposed to fit tightly into the collar. After securing the pipe with screws seal the pipe around the collar. Thats it!