Help. Odd collar size

So the outlet of my stove is 7.5 inches. A 7 inch pipe is to small and 8 inch is to big. Am I missing something here?it has and 8" flue insed of the collar. This is my first wood stove and I'm new to all of this. Sorry for my ignorance. Lol. I'm worried that if I buy the 7" single wall pipe to connect to the stove it will be to small and not seal. What are my options?

Hi Jeff; Welcome to Permies!
I have run into that problem in the past.
You would think that stove manufacturers would stick with standard stove pipe size... but they don't!
What I did, was to create an adapter with sheet metal and pop rivets.
What size is your roof jack ?   7" or 8" ?  
Or is a six inch?
Hopefully its not installed yet.  
In which case I would use 8" single wall to the roof then metalbestos  thru the roof.

Thanks for the response. I haven't installed anything yet, fortunately. I have 7" class a pipe right now so I'll probably stick with that as to not buy more insulated pipe. So what your saying is essentially make my own adapter? Go from collar size to 7" correct? Thanks again!

Yes , that worked for me for many years.
And just because I can... I'll ask if you know about rocket mass heaters???
Enjoy your new stove this winter but do read up on RMH's
Maybe next summer you could build one of them to use less wood and not pollute the area with wood smoke...
Just sayin....

I've never heard of RMHs but I will definitely look into them. Thanks again for your help.

Although you have good pictures, it is still hard to see the full story. Have you tried to take a short length of 8 inch pipe and crimping it yourself to get it to fit inside the stove?

Plan B is even more simple but involves luck . Make a drawing of the inside diameter of the flue exit from the stove by tracing with a piece of paper.  If ...this is the luck part....if you have an old time hardware store in your area ... see if they can cut the pipe to fit.  I have one in my community that will make odd sizes of stove pipe. The owner considers it a challenge.  Of course, the end goal is for them to make an adapter. If the do ....and it works ....buy several.

Plan C....do the same with a small welding shop. If they successfully design an adapter, it will probably last a lifetime. The trick here is to find someone wanting to play with it.