As we discovered in What are the little pieces of wood that come with pre-made canvas for? those wood pieces are called canvas keys.
One of the answers links to a site that covers installing them. I don't get how they are working since it states I am supposed to put them in the mitre slots of the canvas. Would that not break the frame?
Information seems to suggest that canvas keys only have a place for cheaply manufactured frames. Is there something wrong using them on more expensive frames? Do they get used on larger frames as well (ones that are more than 20ft square)?
What are the conditions that would make you want to install canvas keys? How do you install canvas keys properly?