With a butterfly loom, yarn crafters can create beautiful and intricate afghans, scarves and more, but they don't do it by knitting or crocheting. A butterfly loom uses techniques similar to macrame: knotting and wrapping. The butterfly loom company calls this trademarked tool a "magic board," touting it as "truly addictive and great fun." If you agree but want to make your own similar "magic" tool, just apply some simple woodworking techniques and geometry.
Measure your board to ensure it is precisely 27.5 cm by 27.5 cm (11 by 11 inches) -- the size of the standard "magic" butterfly loom (see Tips for options).
Measure a series of marks along the board's edges, 7.5 cm (3 inches) from each side and 2.5 cm (1 inch) apart. You should have six marks on each side.
Mark these measurements into a series of symmetrical "V" shapes, 1.2 cm (1/2 inch) wide at the top and 1.8 cm (3/4 inch) deep. The point of each "V" should be on your measured marks.
Mark an asymmetrical notch near each corner. One edge of each notch is 5.3 cm (2 1/8 inch) from the corner, and the other is 2.5 cm (1 inch) from the corner. The bottom of this off-centre "V" is 1.8 cm (3/4 inches) deep.
Cut out the notches using a saw specially designed for woodworking, such as a scroll saw or bandsaw (see Tips).
Cut off each corner at a 45-degree angle. The new angled edge will be 1.2 cm (1/2 inch) between the notches.
Cut the board in half diagonally, from one corner to another.
Sand all cut edges with medium-grit sandpaper until they are smooth.
Sand the surface of the board and the outside edges (with notches) with the very fine-grit sandpaper. It should be smooth enough that it will not catch or pull on your yarn when using the loom.
Line up the two cut halves, and place the hinges on top, spanning the cut. They should be equally spaced from the corners, about 20 cm (8 inches) apart.
Mark the location of screw holes in the hinges.
Remove the hinges, and drill very small starter holes in the board on the marks you made. Do not pierce through the board completely.
Attach the hinges with the small brass screws.
Flip over the hinged board, and mark a diagonal line from one corner to another, perpendicular to the cut between the two halves.
Mark two holes along this line, about 20 cm (8 inches) apart.
Drill 3 mm (1/8 inch) holes on the marks, and sand the edges of holes with medium-grit sandpaper.
Lay the 25 cm (10 inch) board along the line, and mark it through the holes.
Drill 3 mm (1/8 inch) holes in the board. Use the saw to extend one of these holes into a rounded notch.
Sand the 2.5 by 25 cm (1 by 10 inch) board with medium-grit sandpaper, then smooth it with very fine-grit sandpaper.
Insert one of the 3 mm (1/8 inch) brass pins through one hole in the large board and the hole in the smaller board. Keep the pin loose enough that the small board can swing.
Insert the other pin into the other hole in the larger board and the notch in the smaller one. Keep the pin loose enough that the notch can be readily slipped off the pin.
You may find it easier to mark consistent notches if you use a pattern cut from cardboard. Mark a triangle shape in sturdy cardboard, and cut it out. Lay it on the edge of the larger board so you can trace the "V" shape for the notches. To use the loom, swing the smaller board's notch onto its pin. It will hold the hinges open and keep the board stiff so you can work. When you are finished with your weaving project, slip the bar off its notch, and the board will fold in half along the hinges. You will be able to slide the weaving off the folded loom. Butterfly looms come in a variety of sizes and shapes, in addition to this basic 27.5 cm (11 inch) version. You can make smaller or larger ones by following the same basic steps and adjusting the sizes. The notches will be the same size and shape for most types, though the number of notches on each side will vary.
If you do not thoroughly smooth the faces and edges of your loom with very fine-grit sandpaper, it may catch the yarn as you weave or when you remove the project from the loom.