Every piece in this block is a 90° right angle triangle. There are two sizes. In order to follow the guidelines that ideally you want straight grain on:
- the outside edge of the piece
- the outside edge of the sub-unit
- the outside edge of the block
For those of you who are used to ruler cutting, the most common way to cut 90-degree right angle triangles is to cut strips, cut the strips into squares and cut the squares in half diagonally once. The legs are on straight grain.
Likewise, the most common way to cut 90° right angle triangles with the hypotenuse on straight grain is to cut a square in half diagonally twice.
That means that the hypotenuse of 2 of the triangles is on lengthwise grain but 2 of the triangles have the hypotenuse on the much more stretchy crosswise grain. The pieces will sew and press differently and in some cases, especially with a directional fabric, they will look different.
That will not happen when you cut with templates from strips as shown in our cutting diagrams in the conversion charts. When you see triangles in our diagrams that look like they are laying down it means the long side or hypotenuse of the triangles is on straight lengthwise grain. You will also know that we have cut the strips on the lengthwise grain, ‘cause that is what we do, unless we tell you otherwise : ).
Making the BlockFor me, the pattern of this block was not memorable. I had to keep looking back at the book to make sure I was joining the correct pieces. The triangles are sewn into 4 distinct sub-units in Grandma and they are clearly diagrammed in the book. We have included specific directions for the small triangles on our template conversion chart PDF. The piecing needed for the 4 squares in the center is self-explanatory.
Look back at Old Maid (FMM Chart 7 in the Oct. 2015 archive at right) and you will be reminded of sewing three triangles into a trapezoid. The difference here is that there are three colors. Pay attention… the pieces fit together several ways but only one is the “right" way.
My Grandma Block
Click on the image for a larger view. Click the link to download the Template Conversion Chart for Grandma: