Super Turkey Magnet

You’re cooking and need a magnet to hold your recipe onto the refrigerator, or the stove, or the microwave, or the stove hood.  Or, maybe you just received a “turkey” memo and need to stick it onto your white board or file cabinet or metal office door.  These are the magnets for you.

The key to constructing strong magnets is to channel the magnetic field.  The tighter the field is constrained the higher the attractive force.

Six STL designs are included.  There’s a cooked turkey and a conventional magnet holder with a knob.  Also, there are a designs where two or three pairs of magnets may be stacked for a higher holding force.

List of Material Needed per Magnet

2 – 2mmx10mmx20mm rare earth magnets (4 or 6 magnets if you stack pairs)

1 - 1/8”x3/4” fender washer (a 3/8” washer works and has a 20.8mm outside diameter)

Super glue

Magnet Design

Normally when a magnet is stuck onto a ferric surface the field balloons out from the magnet and loops around to the metal surface.  The field is then channeled through the metal back to the magnet.  But, if a pair of magnets are stuck to the metal surface where one is North-South and the other is reversed i.e. South-North, the majority of the magnetic field tries to loop through both magnets.  Now if a “keeper” is added to the side of the magnets away from the metal surface, the field is channeled by the “keeper” and the metal surface. Thus the attraction to the metal surface is increased.  And, if you double or triple the number of magnets in the stack, the field is increased even more (but a bit less than 2X or 3X).

Printing

I sliced with a 0.25mm Z-step but a smaller step can provide better resolution for the turkey.  I used 20% hexagonal fill and had support turned on. It’s a good idea to print multiple copies at a time so plastic can cool before the next layer is deposited on the small points.  In any case, you’ll probably want more than one magnet.

After printing remove the support on the bottom.  A knife blade twisted in the crack seems to work well.

Assembly

Why the fender washer instead of a regular washer.  The center hole is smaller.  But, any iron washer will do.  A square piece of iron would be better but washers are inexpensive.

Take two of the magnets (stacked/stuck together) and stick them onto the washer.  Slide them to one side of the washer, then flip the top magnet over so both magnets are stuck side by side on the washer.  You now have magnets with a North pole and a South pole stuck to the washer.  Slide the magnets around on the washer until they fit into the recess on the turkey bottom. If you’re stacking two or three sets of magnets now is the time to add the top magnets.  They’ll be attracted into the right orientation.

Be careful handling these magnets.  Letting them snap together can break them.  If you do have a broken magnet the pieces can be used in the second layer of the designs where two sets of magnets are stacked (see photo).  The two pieces can be attached to one of the bottom magnets as though they are a complete magnet.  The pieces will resist your arrangements until they are orientated correctly. 

Apply a liberal amount of super glue in the recess at the bottom of the turkey (or the other design) and push the magnet/washer stack into place.  The goal is to have the magnets and washer keeper embedded in super glue so they can’t come loose.  Let the glue completely polymerize before sticking the magnet onto any surface or letting them attach to each other.  A tiny bit of this glue between two of these magnets will quickly form a permanent bond.