- Add an extra 1/8" to 1/4" (depending on your comfort level) to the square size required for you units. For example, if you are instructed to cut 3-7/8" x 3-7/8" squares, cut 4" x 4" or 4-1/8" x 4-1/8" squares instead.
- Sew two squares together as explained on the previous pages. Cut apart and press.
- Grab your square rotary ruler and cutter. From the front side of the unit, align the ruler so that its diagonal line is lined up exactly with the diagonal line between fabrics (rule numbers will increase from right to left). Let a little bit of fabric extend past the top and right edge of the ruler, making sure that the left and bottom edges of the patch go a bit beyond the desired unfinished size of the HST.
For instance, if your HST should measure 3-1/2" x 3-1/2", the left and bottom edges of the square should lie a bit beyond the rules for that dimension. (This is easier to do than to explain -- play around with ruler placement and you'll see what I mean.)
- Trim away the little bits of fabric along the top and right edges of the HST (dog ears will be trimmed, too).
- Turn the HST around, placing its newly trimmed edges to the inside of the ruler, aligning them with the rules that indicate the correct cut size (such as 3-1/2"). Make sure the diagonal rule is once again aligned with the seam between the patches.
- Trim the little bits that extend past the top and right edges.
- You should now have an HST unit that is 1/2" taller and wider than the finished size of the patch.
Half Square Triangle Size Helpers
After assembly, but before sewing a HST to its neighbors, it should measure 3/8" less on each side than square dimensions the pattern instructed you to cut. Examples:
- 3-7/8" x 3-7/8" parent squares in pattern instructions = 3-1/2" x 3-1/2" units
- 4-3/8" x 4-3/8" parent squares in pattern instructions = 4" x 4" units
Your parent squares will be a bit larger if you decide to assemble the units at a larger size and then cut back.
