Apparently I completely misunderstood your statement. I thought you were talking about something you saw in the photo other than the factory input damper, because the photo was from and odd position and probably confusing. That’s why I backed the picture out to show the entire build. The background info about myself was because I’m new to the forum, and I had seen similar info in one of your post, about how your father was a metal spinner and machinist. I’m not the least thin skinned, but I didn’t realize I was arguing anything. People’s mannerisms In different regions of the country obviously vary greatly. The ends can be closed back up if need be, I can even put the ends back in I’ve cut out, right now there’s no insulating material in the forge at all. I apologize for the rambling post, seems I had several things to address. I have a lot more I wish to say, but I’m obviously not as proficient at typing as you are. You must find it much easier to type than read. It seems odd that’s it’s so burdensome to read a paragraph of background information, but you don’t mind writing a book to address things I’ve not even asked about yet. If I chose to post again I’ll stick to the subject at hand.