Another Oddball DC Fitting - 3D printed and Magnets

[David L Morse]

My old Delta shaper is mobile so I need to be able to disconnect the dust collector and stow it in the minimal space possible. I was originally using two 4" hoses to the combiner on the DC inlet. I've changed that to a single 6" inlet so I needed an efficient combiner attached to the tool that stayed within the outline of the top.

It's sort of possible with standard PVC fittings but I couldn't come up with anything that didn't have at least one badly convoluted path. The maximum allowed profile was also giving me trouble with a printed fitting. I eventually realized that magnetic couplers would solve that problem.

Shaper_5.jpgShaper_2.jpgShaper_3.jpgShaper_4.jpg

[Paul F Franklin]

Nicely done! How long did it take to print?

[Karl Loeblein]

Nice modeling work. Did you need much in the way of supports when printing the parts?

Do you put any of your designs on sites like Thingyverse for people to print or modify? FWIW, I think your design looks like something worth paying for.

[David L Morse]

Nicely done! How long did it take to print?

Thank you Paul. It took almost nine hours. I could have pushed the extruder a bit harder but I didn't want to take too much risk with nearly half a kilogram of filament involved.

Nice modeling work. Did you need much in the way of supports when printing the parts?

Do you put any of your designs on sites like Thingyverse for people to print or modify? FWIW, I think your design looks like something worth paying for.

Thanks Karl. Yes, it did take some support. I try to design around it when possible.

I've put some stuff on Thangs because I can't quite get the Thingaverse interface! The designs are f360. If you're interested I can host them somewhere for download.

[Larry Frank]

Really nicely done !

[Jim Becker]

I think that magnetic couplers can be one of the best "problem solvers" for DC use there can be. That solution is nicely executed!

[Dan Friedrichs]

Very impressive! I love it!

[Wes Grass]

Yes, a very elegant piece of work. Are the fittings retained just by the magnets, or do you have a pilot feature for shear?

[David L Morse]

Yes, a very elegant piece of work. Are the fittings retained just by the magnets, or do you have a pilot feature for shear?

Thanks Wes. The magnets by themselves are enough to resist shear. In fact, the full set of 12 on the six inch fittings is a bit too much for easy removal, which is done with a shearing twist. A side pull on the hose will cause straight breakaway on the far side of the fitting, not shear failure.

[David LaRue]

Very nice! Looks like a fun project.

[David L Morse]

... Are the fittings retained just by the magnets...?

When I answer a question like this with a simple "yes" I'm always left expecting the next shoe. Namely, the question "ok, so how much shear?" After two days I had to have an answer! With as close as I could get to a pure shear force I measured about 12 lb to slide the fitting loose. Now I can relax a bit.

Shear_1.jpg

[Alan Lightstone]

Beautiful solution, David. Very elegant. I wish I had thought of it for my setup (though I have no ability to 3D print. I just went with boatloads of duct tape for attaching the duct to my planer.)

And you actually measured the shear force needed to slide it loose. My nerd king trophy has now been surpassed. The King is Dead! Long live the King!!!

[John Lifer]

Great job. There was a design on thingiverse that was a similar single connection. I used it as basis of connecting my DC hoses. Mine are mainly overhead and use magnets with almost zero friction. And they work well with light duty hose.

[Eric Arnsdorff]

I just saw this and I'm drawing some fittings up currently to 3D print utilizing magnetic attachment.
That's a nice design!!
Which magnets did you use and where did you purchase them?

[David L Morse]

Thanks Eric. I used 12x4 N35 magnets. I bought the first batch from an internet shop called Umagnets. Good selection, good prices, and not too difficult to find what you're looking for, However, when I went back to buy some more the payment page no longer worked. They only accept PayPal and PayPal threw an error. I've tried several times since and no luck.

So I bought some from both Ebay and Aliexpress. Again, good prices but difficult to navigate their selections. Worse, the magnets are only about half the strength of an N35. Fortunately, I allowed for more magnets than it turned out were needed so the half strength is adequate.

I now have a mix of full spec and out of spec magnets and fittings with different numbers of installed magnets but it seems to be working.

This calculator can be a useful resource if you're doing stuff with magnets.