Sawtooth Quilt Block Pattern

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How to Sew a Sawtooth Quilt Block

The Sawtooth quilt block creates a bold, jagged edge design that adds energy and movement to any quilt. It's built from half-square triangles arranged in a repeating pattern.

Materials:

• Fabric pieces in contrasting colors and patterns
• Ruler, rotary cutter & cutting mat
• Sewing machine & thread
• Iron

Instructions:

1. Cut fabric into the required sizes. For a Sawtooth block, you'll need pairs of triangles in contrasting colors or patterns.
2. Place one triangle right-side-up on your work surface. Place the second triangle right-side-down on top, aligning the edges. Pin in place.
3. Sew the two triangles together along the long edge using a ¼" seam allowance.
4. Press the seam open with an iron to create a clean, flat half-square triangle unit.
5. Repeat to create as many HST units as needed for your block.
6. Arrange the HST units in the Sawtooth pattern and sew together in rows, pressing seams in alternating directions.
7. Join the rows together, matching seams carefully. Press the final seams.
8. Once all blocks are complete, sew them together to create your quilt top, then add batting and backing. Quilt as desired.

Covered Corners Technique

Making Half-Square Triangles

On the back of the lighter fabric, draw a pencil line diagonally from corner to corner.

Stack a pair of light and dark squares right sides together. Sew a ¼" seam allowance on each side of the line.

You will end up with something like this:

Now cut along the diagonal line.

Press the seam to set it, then press toward the darkest fabric.

To trim to the exact size, line up the 45° diagonal on your ruler with the seam.

Then carefully trim your block with a rotary cutter.

Making Quarter-Square Triangles

On the back of the lightest square, draw a pencil line 90° to the existing seam on the diagonal:

Butt the central seams:

Sew a ¼" seam allowance on the right and left side of the diagonal line.

Then cut the seam on the pencil line.

Nine Patch Piecing

The secret to the nine patch is pressing seams so they butt when joined. Cut 5 A squares and 4 B squares in the required size. Using chain piecing, join a B square to 3 of the A squares with a ¼" seam allowance. The result:

Next, chain piece the remaining A and B squares to these units:

Your result:

For speed, cut A and B strips and join into A/B/A and B/A/B units. Press every seam toward the dark fabric, then cut across the pre-joined strips:

Same result, but faster:

This methodology applies to all kinds of 9-patch blocks — as long as the block has an underlying 3×3 grid, the principle applies.

When it's not obvious which direction is the dark in complicated blocks, remember the basic ironing plan:

How to Resize Quilt Blocks

The first step in modifying any quilt block is to decide on the finished size. You can base this on doubling a pattern, cutting it in half, or working with your available fabric.

Important: Always remove the seam allowance before doubling or tripling the size. For example, if your pattern calls for 3½" squares, subtract the seam allowances (½"), double the finished block size (3" → 6"), then add the seam allowance back (½"). You'll end up cutting a 6½" piece of fabric.

Resizing Square Blocks

Add ½" to your desired finished block measurement. For a 4" finished square, cut a 4½" square of fabric.

Resizing Rectangular Blocks

Add ½" to both the length and width. To double a block that measures 3" × 4", cut a 6½" × 8½" rectangle of fabric.

Resizing Half-Square Triangle Blocks

Add ⅞" to the desired finished block size. For a 4" finished block, cut 4⅞" squares.

Resizing Quarter-Square Triangle Blocks

Add 1¼" to the desired finished block size. For a 4" finished block, cut your squares 5¼".