So very simple.
Cabochons: I’ve ordered from PinkyNoodles & Cathysjewels and recommend them both. You can order your cabs from lots of different places, do a search on Etsy for cabochon + whatever your interest is. Cats, dogs, ships, skeletons etc. You will find what you want. All of my cabs are 40mm x 30mm. Any size is fine, so long as they are big enough to cover the magnet.
Magnets: I ordered from SunAndMoonCraftKits. I chose the 1/2″ size. Please note these magnets are not toys, these are the type that end badly when small children swallow them. If you have little ones in the house keep the loose (non-glued down) magnets away from kids who are still putting things in their mouths.
Also grab some cheap black magnets at the local craft store. These I seal with clear spray paint just to make sure they don’t mark your fabric. I do suppose you could use two of the rare earth magnets but I don’t because: If you have little ones you’ll have a loose magnet floating around. They are hard to pull apart.
Liquid Nails (E6000 is also good for this, but I’ve had trouble with the glue drying out inside the tube and I’m tired of paying for the whole tube when I only get to use a small amount before the rest spoils).
A pin you don’t care if it’s ruined.
Paper for a work surface & a paper towel.
Hold your magnet up against the back side of your cab and make sure it’ll grab the pin. Sometime I flip the magnet around and it seems stronger on one side. Might be my imagination.
Lay the cab down flat and have the magnet side to be glued facing up.
Put a dot of glue on the magnet. Just a little bit, you don’t need much. It’s called Liquid NAILS for a reason.
LIGHTLY press the magnet on to the back of the cab. I usually rotate the magnet and lightly squish it around to get the glue evenly spread between the pieces. A light touch is best here. Use the pin to remove excess glue that squeezes out, but if you use the right size dot of glue you won’t have any oozing out on you. And voila! it’s stuck.
Oops, you made a mistake. Too much glue, you made a mess, you let the magnet get too close to the other rare earth magnets and it pulled your freshly glued magnet from the cab (ask me how I know this can happen). It’s OK! When the glue is wet you can just wipe it off with the paper towel and re-do it.
See? All clean, like I never screw up. 😉
Over on the right you see a glued cab, on the left you see the stack of magnets. This is a safe distance. When laying the cabs to dry leave about 3 inches between each one (if you’re making more than one, which you should – these make inexpensive awesome little gifts) and you shouldn’t have any issues with the magnets pulling away from the wet glue. I let them dry over night and then they’re ready to use. Just sandwich your fabric between the cabochon and one of the black magnets (note: when putting the black magnet against the rare earth one, there will be a right and wrong side – it’ll be obvious). If you’re just making one for yourself and don’t want to deal with spray painting them, painting them with a coat of clear nail polish should work. I have not tried that myself, so I can’t say for positive, but I think it’ll work ok.
There are also cabochon frames for sale that I think would be a nice addition. You would just glue your cab into the frame, then glue the magnet to the back side of the frame. It’s optional and up to you, just a thought if you wanted to dress your needle minder up.
One last tip, when you’re trying to get those rare earth magnets apart – push them. Pushing/sliding the top most one from the stack is much easier than trying to wedge a fingernail between them and popping them apart.