Jumping on the 3D printer bandwagon

[rob feature]

Noice!

I'm pretty sure I need one of these.

[diy.phil]

there's one with your name on it!

[dumdum]

Noice!

I'm pretty sure I need one of these.

I don’t ‘need’ one... but need is very different to ‘will have one’ in my world

[Theslaking]

Those neo magnets give it away from the other thread.

[Ge0]

Here's my first test print. It turned out decent, but as you can tell by the stringy back, I didn't have the offset adjusted correctly


Here's my second attempt...much moar gooder


Once it was dialed in, it was time to print something practical


It ended up smaller than I imagined...and if I had a nickel for every time I heard that..

---

I love the fact you set your 3D printer up in your bedroom

Ge0

[BigAl205]

That's where all the magic happens

[dgage]

That's where all the magic happens

You must be single.

[Ge0]

You must be single.

LOL! For sure

Ge0

[BigAl205]

[geolemon]

Alrighty... So I literally from-scratch redesigned it.
V.2

Design changes:

• Easy to install - use the cup as a template to mark the two center holes, remove it and use a 1.25" hole saw to cut two conjoined holes... put it back and screw it down.
• Added safety to the base AND the connector.
• Moved the wire entrance/strain relief to a side entry instead of from the top. Just seemed smart.

Still left to do:

• A little clean-up work and tweaks for printability.
• Confirm the distance/recess for recess washers one size. Can't easily do neodymium magnets on both sides "because polarity", and no one is going to want to machine their own countersinks into the backside of magnets.
• Get a test print done.

But that's the cart before the horse...
What is this thing?

This is a magnetic connector that's 3D printed. I was inspired when I saw a ludicrously expensive one that seemed a bit primitive for the price, and wouldn't work for what I'd think you'd want a magnetic connector for - making a removable subwoofer. Seems like a bad idea to have the opportunity for an actively magnetic thing connected to an energized amp - imagine it making contact to anything loose and ferrous in the trunk, or clamping onto the trunk side wall, etc... that would be one expensive dead short!
No one wants to replace an amp. So I thought "How can you build some protection into this?" So the idea is, if something came across both terminals on either the base or the connector, the plastic would block it so it wouldn't cause a short. V.2 has some protection on both the connector and the cup, even though there's less risk on the sub box, obviously.

Besides the printed part, the rest of the parts list is standard and inexpensive:
Uses four #10 flat top phillips bolts with standard locknuts.
Uses four standard yellow crimp connectors, ring terminals.
Designed for 12 gauge speaker wire.
Takes two .76" x .2" neodymium magnets

How does it work?

The connector has some tricks inside.
It's not just hollow, I built in a diagonal wall to help isolate the positive ring terminal from the negative.
I also took the standard thickness of a yellow ring terminal, and built recesses just barely less than that into the magnet surface of the connector...
...so the bolt will sandwich the magnet, to make contact with the ring terminal, against the connector, which holds the nut, to snug it all up tight.
The back of the crimp connector routes inside the hollow inside, separated by that short wall from the other connector.
The wire then goes out the exit channel, which has a recess for a standard 0.19" cable tie for strain relief.
(and really, you'd assemble it exactly backwards as I described, other than cable tie strain relief once it's all assembled)

The cup is simple.
Easy to install - mark the two center holes, drill two 1.25" holes with a hole saw - easier than a jigsaw but you can certainly trace and cut if you prefer.
The same #10 machine screws and lock nuts, but this time holding a stainless recess washer on the surface for the magnet to make contact with.
On the backside, a washer is probably a good idea, then the box wire's yellow ring terminal, then the lock nut clamping it all together.

So here's some 99% done screen captures:




Here's a trip down the speaker wire entry, tried to really zoom down that chute to get a view inside too:

Basically looking into the chamber from where the speaker wire hole enters it - that's the diagonal wall that doesn't completely separate the two chambers (or one of the wires couldn't come out), that you are seeing:


View from below shows some of those details on the connector:

If you look where the crimp connector goes in, you can see that diagonal separation wall again:


Any and all feedback is appreciated -
I've been staring at this for like 4 hours straight so I am probably too close to it to see obvious opportunities for improvement.
Let me know what you think. Feedback please.

PS. I did read an article on how to reduce printing costs while staying at a Holiday Inn Express... but I could surely use advisement from people who have actually printed something. I'm still shopping for my first printer. My whole side-nozzle idea sounds difficult, where a top exit would be easy, for example.