Threaded flexy/PVC ducting coupler

This "coupler" is designed for standard PVC ducting to be joined to flexible Polyurethane/PVC hose. The hose join is on the outside of the hose which compared to couplers made by placing the hose over ducting means air flow is less restricted.

The STL files are designed to suit 4" hose and 4" PVC ducting.

The *.*sin.STL file produces a sinusoidal threaded section that is the most forgiving as you don't need to be too specific about getting the radius of the flex side of the coupler just right, but it will also be the more restrictive, although no more so than a shallow bend in the flex.

The *.*cir.STL file produces a semicircular threaded section that less restrictive than the sinusoidal threaded coupler but is not as forgiving in terms of fit so you may have to play around with the sizes in your slicer. near in mind that if you adjust the thread you will end up adjusting the unthreaded section. If you can use the SCAD file you can adjust these independently.

The SCAD fil