Does anyone have any suggestions for connecting this misaligned situation? The bottom hole is the microwave vent and the top hole vents to the outisde of the wall. The appliance installer told me to buy a roof cap, which I did. Now the company is saying they can't install it due to the misalignment. Any suggestions or solutions would be most appreciated. Thank you.

I am heating a test chamber and delivering that heat via duct work. The heating element is forced air based and is located external to the chamber. At some point the duct work will need to pass into the chamber from which point I will use either an elbow or flexible duct to aim the flow of heat. Most couplers have a ridge on both ends for the respective duct to butt up against. These ridges are larger than the duct diameter which means cutting a large enough hole in the side wall of the chamber to allow a coupler to pass through including those ridges will leave a good amount of slop as the hole will be too large for the center of the coupler where the ridges are not present. I was considering a starting collar such as this: [url]https://www.menards.com/main/heating-cooling/ductwork/ductwork-fittings/flowtite-plain-duct-fitting/21706000rb/p-1444432238020-c-14260.htm?tid=8568290988290135205&ipos=42[/url] Where i can easily secure and seal the chamber against the flange and mount the incoming duct to the protruding end. Which leaves the open end inside the chamber. Like I said ideally id like to have another portion of ducting to direct the airflow internally. Can I insert a duct into the open end of this flange? Hopefully this makes sense. Otherwise I'll just use a section of straight duct and run a coupler on both sides of the chamber wall i suppose. TIA.