I did something along the lines of Larry's idea with my Walker Turners. With 1/2" thick cast iron doors, cutting a hole in them was not an option so this is what I came up with. I don't have any picture of the finished product, but you should get the idea. With a bit of putty, bondo and some paint it looks great and performs just as well. With the 4" port there's plenty of air flow and virtually no dust escapes. I has originally planned to use rare earth magnets for mounting, but a perfectly placed existing threaded hole was used for mounting.
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Mike