Assemble and Add Middle Border
1. Referring to Diagram 9, sew together two light blue print 1-3/4x10" strips and three assorted 1930s print 1-1/2x10" strips to make a border strip set. Press seams in one direction. Repeat to make 10 border strip sets total. Cut border strip sets into 60—1-1/2"-wide border segments.
2. Referring to Diagram 10, sew together one light blue print 1-3/4" square, three light blue print 1-3/4x1-1/2" rectangles, and six assorted 1930s print 1-1/2" squares in four rows. Press seams in one direction, alternating direction with each row. Join rows to make a border corner; press seams toward light blue print 1-3/4" square. Repeat to make four border corners total.
3. Referring to Diagram 11, sew together 15 border segments in a row, rotating every other segment so seams interlock. Add a border corner to left-hand end of row; press all seams toward border corner.
4. Centering the assorted print squares, trim long edges of Step 3 row so it is 3-1/2" wide including seam allowances (about 3/8" beyond points of assorted print squares) to make a middle border strip.
5. Repeat steps 3 and 4 to make four middle border strips total.
6. Align midpoints of a middle border strip and one edge of quilt center. Pin at center, then pin rest of border to quilt center; ease border strip to fit if necessary and handle it carefully to avoid stretching the bias edges. Sew together, beginning and ending seam 1/4" from corners of quilt center.
7. Repeat Step 6 to add a middle border strip to opposite edge of quilt center. In same manner, join remaining middle border strips to remaining edges of quilt center, mitering corners. Press all seams toward inner border. To miter each corner, begin with a backstitch at the inside corner and join ends of middle border strips with a 1/4" seam. Press seam open. The quilt center now should be 27-3/4" square including seam allowances.