Switchable Magnetic Key Ring

Sticking your keys everywhere it's cool, but magnets attract all the time and that can be a downside, sometimes you drop your keys to a pocket full of screws, and you end up with a bit of a mess.

What if you could turn on and off the magnet ? Spoiler, you can, and you don't need electricity, just a twist of your fingers.

You will need the following for making an exact copy of mine, hopefully at the end of this instructable you understand all you need to make one following your needs!

• 3d printed pieces (3 of them) as A, B, C
• M3x12mm Screws (4 of them)
• 8 x 3mm Circular Magnets (6 of them, the stronger the magnet the better)
• Some cord or wire, be as stylish as you want to join the key ring with the body
• Standard key ring

Optional:

• Some superglue, depending on your printer tolerances
• A screwdriver, not necessary but may make your job a bit easier

3d Print settings:

• You have the PrusaSlicer file with my settings at your disposal.
• Use your normal settings, the only special need is low layer height, 0.16mm or lower works fine.

Time:

• Around 40 min print
• 5 min assembly

Once you have all the parts ready, you are only 5 minutes away (probably less) from your Switchable Magnetic Key Ring !

STEP 1: Add a screw all the way to the end (I forgot int the step II photo)

STEP 2 : Push 3 of the magnets until contact with the screw, orientation does not matter.

STEP 3: Add another screw as Step 1.

You can see in the materials photo that all are named with a letter, each step has a reference of the parts needed for that particular step.

Follow the self-explanatory step by step photos and you will end up with your first half done

In this stage you will assemble the second half and join the part from the previous step with the just assemble one

Follow the steps and you are done!

STEP 4: Same procedure as Steps 1,2,3 with the other big printed part.

STEP 5: Insert part A int part B

STEP 6: Insert part C int the hole of the part AB assembly, you may want to add some glue, depending on tolerances.

STEP 7: With the cord or wire of choice join the assembly with the key ring.(I used a piece of steel wire for the photo as the fish line was harder to see, but it works great)

DONE!

We have 2 sets of magnets joined by a metal rod, as the screws of each part make contact, there are 2 cases:

• Same sign same side:

This is the case of the first image, as you can see the polarity of the magnets is the same on the 2 sets, explained roughly this polarizes each side with a different sign, the magnetic field closes through the air from positive to negative, making the key ring magnetic and able to stick, like you would spect of a magnet.

• Different sing on each magnet:

This is the case of the second image, when this happens the field closes through the screws from one magnet and ends on the other, there are no field lines through the air (there is some magnetism left but is very weak) and thus the key ring does not attach to ferromagnetic materials, turning the magnet off

This said, all you need to do to switch the magnet on or off is to rotate one of the parts half a turn, 180º, done!