Originally Posted by PatriceJ
the "match" for half-square triangles is easy. just add 7/8ths of an inch to the finished size of the square.
3" block finished.
cut the squares 3-7/8ths inch square
draw a diagonal line down the middle
put that square face down on a square of the contrasting fabric
draw another line 1/4" to the left, and a third line 1/4" to the right of the center diagonal line
sew on the left and right lines
cut them apart
voila!
Better yet, cut the squares 4 1/4 then do as Patrice says. Trim your slightly oversize blocks to exactly 3" with the diagonal very precisely right on. Takes an hour more for 50 some triangle squares, but it's worth it.
tim in san jose