In this part we are going to attach A to B and B to C. If you've been following the QAL, the same basic rules apply - lots of pins and go slow.
1. Pin A to B with A, the pointy bit, on top. Place your pins perpendicular to the seam line as shown here.
2. Pin at each "junction" - i.e. at the edge of each segments and at the junction between triangles.
3. Put your stitch length back to normal. Set your machine to slow and needle down if you have these options.
4. Put your needle down at the start of the seam and sew two or three stitches. Leaving the needle down, raise the presser foot and jiggle, pull etc the fabric so it lines up together as far as the next pin. Sew that section slowly and carefully, easing (stretching) if needed.
TOP TIP: Make sure that, when you get to the next pin, you have no spare fabric on top or bottom.
5. Stop at the pin, leave the needle down, raise the presser foot, jiggle the fabric to line up as far as the next pin. Sew to the next pin.
6. Repeat until you reach the end of the fabric.
8. Next cut out your C template. Given that this template will not give you a square block, I cut it out a few inches away from the edges of the fabric which gives me more flexibility on block size. On this block are short green lines marking the points at which this template will meet with the triangle points on the A template. Mark these on your fabric - I cut small (3/8" notches) into the fabric.
9. Pin this segment to the A/B piece along the top of the triangles. Have the C fabric on top. Again, pin at each junction - aligning the top of the triangles with the notches on the C fabric and with pinheads sticking out to the right of the fabric.
10. Once again sew two or three stitches then, leaving the needle in the fabric, lift the presser foot and jiggle the fabric to align it up to the next pin. Sew to the next pin. Needle down, presser foot up, jiggle fabric to align to the next pin. Sew and continue to the end of the fabric.
11. Press this seam towards the C template because of the bulk at the tops of the triangles.