For sale is a great item for Blacksmiths and small-scale forging operations: a Dayton 1/20 HP Blower Motor and Squirrel-Cage Fan with Attached Adjustable Damper Port. You can use it to adjust the flow of air to your coal forge. 1/60/115V, Single phase electrical input. Damper port is fully adjustable from closed to wide-open, and has a set screw to maintain position. 2-7/8" O.D. of aluminum damper port.