Patchpieces: Setting triangles

QUICK CUTTING METHOD FOR SETTING & CORNER TRIANGLES

As a quilting teacher, one of the most frequently asked questions I am asked is, "How do I determine the cutting size of setting and corner triangles for a quilt with blocks that are set on point?" Now here is the answer. Feel free to print this and share with your quilting friends and guild.

Use the formula below to calculate the size of the square needed for quick cutting. You will need to know the size of the finished block.

Finished Block size = _______

Setting Triangles:
1. Finished Block size x 1.414 (round to nearest 1/8”) = Finished diagonal
2. Add 1.25” (or 1 1/4”) to Finished diagonal measurement to obtain the size of the square to cut.
3. Cut one square and cut in half diagonally TWICE for four setting triangles. Repeat to cut the number of setting triangles needed.

Corner Triangles:
1. Finished Diagonal of block ÷ 2 = Finished short side of Corner Triangle.
2. Add .875 (or 7/8”) .
3. Cut two squares in half diagonally ONCE for four corner triangles.

Setting Squares: Finished Block size + .5 (or 1/2”)

EXAMPLE:
Finished block size = 6"

Setting Triangles: 6 x 1.414 = 8.48 (round up to 8.50)
8.50 + 1.25 = 9.75 (or 9 3/4")
Size to cut square, 9 3/4"

Corner Triangles: 8.50 ÷ 2 = 4.25
4.25 + .875 = 5.125 (or 5 1/8")
Size to cut square, 5 1/8"

Setting Squares: 6 + .5 = 6.5 (or 6 1/2")
Size to cut squares, 6 1/2"

Decimals to Fractions

.125	1/8
.25	1/4
.375	3/8
.5	1/2
.625	5/8
.75	3/4
.875	7/8

Acrobat Reader/PDF version:
settingtriangles.pdf