Harbor Freight Dust Collector to 4" PVC Intake Fitting

thingiverse

This adapts the roughly 5-inch intake on a Harbor Freight single stage dust collector to allow it to accept a more standard 4-inch PVC hose. It replaces the Y fitting on the impeller intake, using the factory bolt to lock it into place. It's designed to be a tight fit. You'll need to work it into place carefully, and try to keep the bolt hole in the adapter aligned with the bolt hole in the impeller intake. It won't turn easily once you've pressed it on.