crimped stove pipe slightly larger than thimble opening

My 8" bought crimped stove pipe is slightly(maybe a sixteenth) larger than my chimney thimble opening. I can wedge it in there to go about a quarter of an inch into the thimble and stop. How do I shrink slightly the diameter of the already crimped stove pipe so it will go further into the thimble. Thanks.

Aside of having a crimp making tool, it will be difficult. I have hand pliers made for that purpose. The crimps must be made deeper to shrink the diameter of the pipe. I don't know if you can twist each crimp a little with heavy duty needle nose pliers and be effective. The other way would be to use a cold chisel and a vise. With the jaws slightly open, place the crip end over the end of the vise jaws and use the cold chisel and hammer to tap each crimp bottom groove.

You should use a chimney adapter in the thimble, not stovepipe.

It is the chimney adapter I'm having trouble getting into the thimble.

You need fluting pliers.

Not sure about your problem but these work to add more wrinkle to reduce the diameter of the pipe. Be sure you have the correct components, a sound chimny is important.
http://heating-and-cooling.hardwarestor ... mpers.aspx