The design of the ancient pyramids seems simple enough in the abstract: four equilateral triangles positioned around a square base. However, when working with a model-building material of significant thickness (i.e. a wooden board), the angles and neat seams of the shape are surprisingly difficult to replicate. The key lies in how you cut the edges of the material, a practice known in woodworking as "bevelling."

- Skill level:
- Easy

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### Things you need

- Table saw with tilting blade and adjustable rip fence
- Five 12 x 12 x 5/8-inch pine boards
- 12-inch ruler
- Pencil
- Drafting compass
- Acrylic epoxy (e.g. Gorilla Glue)

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## Instructions

- 1
Use the ruler to mark a point on one edge of a 12 x 12-inch board that is six inches from either side, or exactly in the centre of that side.

- 2
Mark a point along the opposite side that is six inches from either corner, or exactly in the centre.

- 3
Use the ruler to trace a line that connects the two points. If done correctly, this should divide the board into two 6 x 12-inch rectangles.

- 4
Load the pencil into the compass and set it so the tip of the needle and the tip of the pencil are exactly 12 inches apart.

- 5
Place the compass needle on the corner of the board and trace an arc that intersects the line in Step 3. Label this point of intersection "Point A."

- 6
Use the ruler to draw a straight line from the corner of the board where the needle is to Point A.

- 7
Use the ruler to draw a straight line from Point A to the corner adjacent to the needle, thus creating a mirror image of the triangle in Step 6.

- 8
Erase the line you drew in Step 3, leaving you with the outline of a 12-inch equilateral triangle.

- 9
Repeat Steps 1 through 8 on the other three boards.

- 10
Cut each board along its pencil outline with the table saw. You should then have one 12 x 12-inch square board and four equilateral triangles that measure 12 inches on each side.

- 11
Turn the elevation wheel to lower the table saw's blade so that only 1 1/2 inches extends up from the tabletop.

- 12
Set the "Blade Tilt" handle underneath the table saw to 45 degrees. Tilt the blade toward the rip fence.

- 13
Set rip fence 10 3/8 inches from the base of the exposed blade, or where the blade meets the table.

- 14
Line up the edge of each triangle with the base of the saw blade. Slide each triangle along the rip fence so the blade cuts the board's rectangular edge into a 45 degree incline. Make sure the same side of the board is facing up when you cut each of its edges. The result should be a 12-inch equilateral triangle with a 5/8 inch-wide bevel around the edge.

- 15
Place a thin bead of Gorilla Glue or other acrylic-based wood epoxy along the middle of one of the triangle's bevelled surfaces.

- 16
Press the bevelled surface of another triangle against this glued surface. Line up the ends of both sides and hold the two triangles together for about five minutes.

- 17
Repeat Steps 15 and 16 with the two remaining triangles.

- 18
Pour a bead of epoxy around the entire border of the 12 x 12 board, about 1/4 inch from the edge.

- 19
Pour a bead of epoxy on the remaining bevelled surfaces of the glued triangles in Steps 15 and 16. Press two adjacent bevelled surfaces of this glued pair onto the surface of the square board.

- 20
Press the glued pair in Step 17 onto the square board while sliding two of its bevelled edges up against the epoxy-covered surfaces of the first glued pair. In other words, all of the bevelled edges from all of the triangles are now on the inside of the pyramid.

- 21
Keep all five pieces pressed together for about 30 minutes, wiping away oozing epoxy from the seams. Let the pyramid dry overnight.