I needed a way to consistently place magnets with the correct orientation, so I modeled these to place magnets.

Non-printed Parts required:

• 2 6mm x 2.7mm magnets
• 2 30mm x 4mm springs
• 2 M3 x 40mm bolts

Spring kit that I used: https://www.amazon.com/dp/B08KD5Q2P7?ref=ppx_yo2ov_dt_b_product_details&th=1

Magnets that I used: The magnets that I used are no longer available on amazon, but I'm sure some 6mm x 3mm magnets would work just as well. (you could also adjust the magnet height parameter of the model to accomplish this).

Using the parameters of the fusion 360 file, you can adjust the part to meet your needs. The model is fully parameterized with ONE exception. The threads are not able to be parametric in this model, so you will need to edit the thread features at the bottom IF you edit the radius of the tube. The threads will need to be changed to a thread close to your new outer diameter (tube inner radius x 2 + 0.4 cm). The model currently has 14 mm threads for the 0.5 cm radius (giving a outer diameter of 14mm.

Printing:

Print each set of caps in a contrasting color (to identify the polarity of the magnet).

I printed in PLA with a 0.6mm nozzle and 0.2mm layer height, and only used support with the “carriage” piece.

Print in the orientation as they appear in the slicer.

Assembly:

1. Screw the bolt into the plunger to cut the threads.
2. Unscrew the bolt from the plunger, and push it through the carriage.
3. You can take this time to glue that magnet into the carriage with the bolt OR wait until after step 5 to make attaching the plunger easier.
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4. Place the bolt and carriage into the tube (make sure it is seated on the side of the tube that has a matching angle) and place the spring onto the bolt on the opposite side.
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5. While pushing onto the bolt / carriage or magnet with a allen wrench (or other tool), screw the plunger onto the bolt to compress the spring.
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6. Screw the caps onto the top and bottom (make sure the glue has dried prior to attempting to use).

Use:

Depress the plunger attach a magnet to the bottom, release the plunger to release the magnet.

The strength of the hold can be adjusted by screwing the plunger onto the bolt more (for it to release more easily) or less (for it to hold onto the magnets more tightly).