I have a new fairly quiet but fairly small ShopVac and an old large screamer. The old one works as a blower as well, and the output is a standard 2" hose connection just like the input. So it occurs to me that I could daisy chain it to the new one and use it as a big chip collector. I would probably use the foam filter so as not to introduce too much resistance. My guess is that there are fan blades in there that would spin and turn the motor. Would that do any harm?