Hello everyone! I have an idea for a piece of jewelry and I need
some help as to how I would go about carving the wax model.
Basically, I want to carve a four-sided pyramid out of a perfect cube
piece of wax. Is there any way I could cut off the sides to make it
exact? I’ve been trying to think of how and I’m not sure if there
really is a way to get a “perfectly shaped” geometric shape such as a
pyramid out of wax. Thanks for your help! 
Your question relates more to geometry if I understand it. Basically
you find the centre of the square on the top of the cube. This is
what you want to connect to each of the four corners. If it were me,
I think I wouldn’t carve it, I’d melt it on a flat surface. I’ll be
interested to read what the wax carvers have to say.
Geometric shapes are best constructed, not cast. If you need to cast
the finished piece, the model at least should be constructed. You’ll
be able to get the sides dead flat and will have perfect control
over the thidkness of the piece. Figuring out the angles of the
miters is fairly straightforward geometry. Or you can construct a
cardboard maquette and measure the angles with a protractor.
Elliot
You want a perfect geometric shape, or close?
You can carve it out of wax.
You can carve it out of wood, make a mould and pour a wax.
You could make it out of plasticene, make a mould and pour a wax.
You could ask a CAD house to make you a grown wax model.
There are lots more ways to do it.
Regards Charles A.
Carving a pyramid in hard carving wax is not difficult, but involves
precision with your layout and carving technique. Your first “test”
of your technique is carving a perfect cube out of wax, with smooth
sides. You’ll need a broad, coarse file, which won’t load easily with
wax, but will still leave a relatively smooth surface on the wax. A
machinist’s square will be required, to check for absolute squareness
on all sides, and an accurate calipers (digital recommended) to
measure each side of the cube. Once you’ve managed to carve a perfect
cube, with smooth sides, you have graduated to “Advanced Wax Carver”
status, as there are not many people who can accomplish such a feat
by hand processes. ( You can DO this!) Once you have the perfect wax
cube in hand, you can take your dividers and draft two faint,
accurate lines through the top surface of the cube, splitting the top
into 4 equal quarters. You should have a perfect “bulls eye” cross in
the center. That cross’s center represents the very tip of your
pyramid.
Carving the two opposite sides is the easiest, as you have the
guide-line on the top to carve to, to keep flat sides on your
pyramid. The last two sides are trickiest, to keep your planes even
with the bottom of the pyramid. Don’t file over your guide-lines, and
keep your sides flat, and you will carve a perfect pyramid.
I would recommend hollowing out that pyramid from the bottom,
leaving approx. 1 mm wall thickness for casting, or you will have one
monsterously heavy casting, probably with porosity.
Molding a solid pyramid will probably mean “sucked-in” sides due to
shrinkage of the liquid wax in the mold.
Good luck!
Jay Whaley
Basically you find the centre of the square on the top of the cube. This is what you want to connect to each of the four corners.
Barbara is correct enough, though I’d say you connect the four bottom
edges to the top point, making triangular planes. Six of one, half
dozen of the other. It’s easy. The hard part, as always, is the
craftsmanship. Getting the planes straight, square, flat and all the
edges straight from base to top point is not so easy. But yes - you
just remove material till all the lines and points meet up.