Tuesday’s Triangle — Multiple Half Square Triangles

10 08 2011

Let me get this out of the way — I know it isn’t Tuesday!  I completely missed last week on here, and I’m a day late and a dollar short this week.  I’m afraid if I let this slide again the whole idea will fade into oblivion!

Today’s tutorial is on making multiple half square triangles at once.  This time I started with two rectangles of fabric.

I determined the width of the rectangle by adding 7/8 of an inch to the desired finished square size.  Then I multiplied that by the number of squares wide I wanted to mark and added a half an inch.  I did the same for the length.  In my example I’m making 1 inch finished squares and I decided my marked squares would by 5 x 3 so this is how the math looked.

Width = (( 1 inch + 7/8 inch) x 5) + 1/2 inch

Length = ((1 inch + 7/8 inch) x 3) + 1/2 inch

In this case my cut rectangle was 9-7/8 inches by 6-1/8 inches.  The rectangle id be made to whatever dimensions and quantity of triangles one wants.  Just be aware that at some point the piece will become unwieldy.  I wouldn’t want to use this method for the full width of a piece of fabric.

Next mark a grid on the wrong side of the lightest colored fabric.  Allow a 1/4 inch allowance all the way around the edge, this takes care of any shifting while sewing.  I marked the 1/4 inch at one end and then just kept marking another line 1-7/8 inches from the previous one until reaching the other side of the rectangle and then did exactly the same thing the other direction.  If the final line isn’t exactly 1/4 inch from the edge it doesn’t matter.

Next mark a diagonal line one direction through the square.

Layer the two rectangles right side together and line up the edge of a quarter-inch presser foot with one side of a diagonal line.  Stitch from one end of the line to the other.

At the end of the line lift the presser foot and rotate the fabric to line up the foot with the other side of the line.  Don’t bother to cut the threads.  Stitch from one end of the line to the other and then move to the next line.

Continue in the same manner until each diagonal line has stitching on both sides.

Now it is time to cut the triangles apart.  This is IMPORTANT!  Start by cutting either the horizontal or vertical lines NOT the diagonal lines.  I put the rectangle on a cutting mat and carefully cut on the vertical lines.  Life will be easier if the pieces aren’t moved as they are cut.

If you haven’t moved the pieces that were cut and your mat is small enough, carefully pick it up and rotate it 90 degrees.  Then carefully cut on the other straight line (it will be either the horizontal or vertical lines).  If you did move the pieces or they shifted while turning the mat, it may be necessary to cut each square individually.

Now the squares can be cut apart on the diagonal line.  It isn’t as important to cut exactly on the line at this point, because the cutting is taking place in the seam allowance.  However, it is important to not just start cutting all the diagonal lines with all the pieces still in place.  (If you do you will cut off the corner of each half square triangle.)  You can create a checkerboard pattern by picking up every other square and cutting the remaining ones in strips.  The mat would again be rotated to ease the cutting process.

The other option is to cut all the squares individually.  I did cut the squares I picked up separately.


Once all the triangles are cut, you will notice there are 4 or 5 stitches across the point.

Gently grasp the dark side of the triangle in one hand and the light side in the other near the point and pull.  (This is far easier to do using both hands rather than one while holding the camera with the other 😀 ).

Those stitches will just pop out

The half square triangles are ready to have the seams pressed toward the dark side.

After pressing I have 30 half square triangles that will finish at 1 inch square.  Notice I ended up with twice as many blocks as the squares I marked on the original rectangle.

As I already mentioned this is a good method when you need lots of half square triangles that are the same.  There is minimal waste.  I know there is a different sewing pattern out there, where one just keeps pivoting to sew all of one side of the line, but it required too much thought today to figure it.  There are books that have that marking and stitching pattern, but I don’t mind dragging a little thread.  The end results are the same.




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