4" Dust Coupler

I wanted a quicker way to connect and disconnect different tools from my dust collector, flex hose and main trunk. After searching for a while there were many available, some commercially, some privately and some on printable. Everything had something that I like but also things which I didn't like. I took inspiration from Izzy Swan's magport, FPF mag duct and and a number of others. 

My design criteria are as follows:

1: Must connect by press fit on rigid side.

2: Screws into flex hose

3: Quick connects without needing to twist to lock anything.

4: Connection must be strong enough to hold suspect 2m of flex duct from ground.

5: Connection is resistant against sheer force disconnection.

6: The feeling when the coupler makes connection must be akin to when Thanos inserted the mind stone.

As such my solutions are as follows.

1: The receiver is tapered 0.5mm to allow press fit into all 4"ports (at least the ones I have on my machines)

2: A part called the flex screw has a left hand screw which screws into the flex hose for airtight connection.

3: Slip collar and corresponding flat stop on flex screw allows the collar to freely rotate and establish the connection to the receiver.

4: Different thickness magnets were tested to determine what strength was preferable. 10mmDx5mm disk magnets resulted in a 11.5kg holding force. 

5: The flex screw is double male ended. It has a male connection to the slip collar and protrudes from the slip collar and has a male connection to the receiver. 

6: Magnets

Aesthetics is also important which is why I made the magnet locations elongate much more than the magnets. It also doubles as grip to twist and break the connection. 

The CONS: 

In order for the slip collar to work it must be a transition/loose interface which in dust collection terms a potential point for a leak. but the flex screw is designed such to minimize the potential. If it becomes a problem a o ring or thin piece of rubber/foam can be seated into the receiver seal the leak. I have 6 sets of these and haven't had an issue yet. 

It uses a bit of filament. at 15% infill (more than enough) I get 3 full sets or 25% infill only 2 sets from 1kg. 

The magnet cost adds up.

As for print settings:

FIlament: eSUN PETG solid blue

Temp: 240deg

Bed temp: 75deg

Support: Not needed

Speed: 70mm/s

Final assembly notes:

Alternate the magnets when installing. This would mean that you don't need to keep track of polarities and couplers will be all interchangeable.

The magnet holes are slightly oversized but should still be a press fit. Some channel locks or adjustable pluming pliers help with seating the magnets.

Make sure to seat the magnets flush or slightly recessed. This gives the best possible connection for the slip wring and the receiver. 

Put a dab of superglue either in the magnet hole or over the magnet in the end to ensure the magnets don't come back out.