Tuesday, 12 February 2013

Beginning blocks 3b

Crow's Nest variation

Since block 1a we have been rotary cutting squares and oblongs whether singly or from strips or from sewn strip sets. Now we are rotary cutting half square triangles (HST's) where a square is cut in half diagonally to yield two triangles with the straight grain on the shorter right angled sides. We have learned that to cater for the extra seam allowance we need to add 7/8" to the finished square measurement. We are making a 12"  nine patch block so the finished squares measure 4".
Preparing to cut 4" + 7/8" squares in half to yield 2 HST's

Two HST's from one square

To make a square from two HST's  we need to cut 4 & 7/8" squares; we get two HST's from each square and for this block we need four so we cut two 4 7/8" squares and cut them once diagonally across.

Quarter square triangles (QST's) where the square is cut twice across diagonally have the straight of grain on the long side which lies on the outer edge of the square. One square yields four QST's. To cut these we have to add 1.25" as there are more seams to accommodate. Here there are four of one colour and four of another so we cut a 5.25" square of each and cut twice diagonally across. I try to keep the square stable when doing this so I don't lose the diagonal line for the second cut.
Cutting the 5.25" square

The second cut, easy because the fabric hasn't shifted.

Four QST's

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