ducts

I am designing a bunch of ductwork parts for 24ga sheet metal for hand assembly (not welded), and I can't figure out how to add seam allowances for something like a Pittsburgh seam. In a flat layout, I'd just add 1" on one side of the rip joint for the pitt and 1/4" on the other side of the rip for the flange. But when the…

I'm trying to recreate a model I found in onshape. However, I'm struggling with how to recreate the angled remove. This picture shows what I'm referring to: Here is my model: It doesn't have to be exact, but something close. The reason this is angled in this way, is a straight cut through will go right through the channels…