Wednesday, May 16, 2012

Tricky Triangles & How to Fix Them

I received an email from a quilter asking about one of the blocks in my Block a Day Calendar by Martingale. It seems that she and her quilting group were finding that their block points were being lopped off - that perhaps the cutting dimensions were incorrect (and they could be - I'm only human). She referred to several blocks, but I am only going to reference one: The Right Hand of Fellowship.
You can see ALL of the blocks (366) at my website and the 12 quilt projects made with them. Just click on the calendar image on the right ==>>>>>
Right Hand of Fellowship from the Quilter's Block a Day Calendar by Debby Kratovil

I looked at the cutting directions and knew that they were right. My suspicions tell me that it's all in the way the triangles are cut and then POSITIONED before sewing. I created a step by step photo lesson to illustrate this. IF YOU CLICK ON EACH IMAGE HERE, IT WILL TAKE YOU TO A LARGER IMAGE THAT SHOWS THE BLOCK UP-CLOSE-AND-PERSONAL


Triangles must hang over sides of square
 To begin, notice in the picture above that there are 3 unique patches: a small triangle (cut a square into 4 equal triangles), a large triangle (cut a square into 2 equal triangles) and four corner squares.
In the pic on the left, notice how the small quarter-square triangles are aligned with the square patch. THIS IS CRUCIAL!! The little corners of the triangle MUST hang over equally on the square's sides. This is in order to accommodate the 1/4" seam allowance. Once sewn, press the triangle AWAY from the square.

Triangles hang over sides of square again!
Sew two triangles to the square as shown in the next pic. Press the seam outward as before.

Notice the 1/4" seam at top
Two opposing sides of block; notice 1/4" seams at edges
Can you see the 1/4" seam allowance at the top of the 3rd picture? This is needed so that when the block is joined into a larger quilt, the point of the square isn't lopped off. That is the magic of this sort of triangle. What is the formula for quarter square triangles? Finished size PLUS 1-1/4" for seams. For this 9" block, the finished size that the triangle occupies is 3", so we cut a 4-1/4" square (3" plus 1-1/4") along both diagonals to yield four of these triangles.
Block parts before joining. Notice the 1/4" seams.
 Now we get to the larger triangles which were cut from a square also. But these are only cut into two triangles each, so the FORMULA is? Finished size PLUS 7/8". So, the finished size that the triangle occupies is 3". For this we cut 3-7/8" squares.
Wrong side of partial block

Block almost finished!





Units are joined. Notice at the block's underside (scroll down) that it's OK if you press seams open. In fact, I do it often in order to reduce bulk.


Sewn block - notice seam allowance around ALL edges
 Block is finished but I have yet to trim off the little triangle ears. I leave them on the block until it is finished. I leave them on while I am constructing the block because they aid in patch alignment.
Block is 9-1/2" UNFINISHED

1 comment:

  1. I know you posted this tutorial over a year ago, but having just found it, I want to say Thank You! I am just finishing a quilt that is all HSTs and I wish I had read this tutorial first and that I had known to leave the "ears" on, I am sure it would have helped!

    ReplyDelete

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