Using a furnace fan for dust collection.
I have a Delta dust collector which sits in the shed behind my shop. I am also surrounded on three sides by widder women who either go to bed with the chickens or sleep in 'til 9 am. The turbojet sound is not amusing to them. Having a squirrel cage furnace fan with an outlet of 5" by 8 1/2" that will blow your wig off, I wondered if I could use this quiet fan as an auxiliary dust and shavings collector with my lathe.
I boxed it in with some OSB (or as my brother says, SOB) and mounted a fixture on the top to attach a 4 inch flexible pipe to the cyclone. It would suck smoke, but nothing else. I realized it was not getting up to full speed with this obstruction, so I used a hole saw and made a 2 inch hole in the case. The fan turned faster but the hose suction was the same. I made 2 holes, same story.
I realized that even if it worked, the motor would be in the air stream for sanding dust and would not last long, but this was a prototype.
Conclusions: 1. This setup would only work using at least an 8 inch hose. 2. The motor would have to be outside the box for it to last. 3. The motor as supplied is too weak to overcome air-flow obstructions.
If I come into possession of a belt-driven model that I can attach a larger motor to, I will probably try again. I am intrigued by the quiet running of this type of fan.