My original handle was for the 4-5mm deep version of this magnet. This is for the deeper, 12-15mm deep version. These deeper magnets have a bolt or large screw on the back side instead of a screw going through the face. These are also a LOT stronger. This grip/handle has a larger inside pocket and a sleeve for extra strength and grip.

For a really good, secure bond, I mixed up 2 grams of epoxy. Put a drop on the threads and screwed in the bolt/screw as far as it would go (do a dry fit first!) Then I coated the inside of the opening with epoxy, making sure to fill the center hole. Drop in the magnet, with the bolt down. Rotate in a circle and apply light pressure. Spin a little in both directions to ensure a thorough coating. Epoxy will seep up and out the sides. With 2 grams the amount that seeped out was just right. Any excess can be wiped off.

CA (super) glue would also work, but you'd need a lot and the bond is better with epoxy. I also have a version of this without the sleeve.

The smaller holes (3x2mm) are for surface area for the adhesive to grip.

Print with the opening up and you probably won't need supports.