Thank you, both, Annis and Nancy! Even though I followed Janet Stone's directions for the BOM block, I really wanted to learn how I would draft this block from start to finish myself in any size. Where I was getting messed up was on the size on the first innermost square and I think Nancy visually cleared that up for me with the comparison to HSTs. If I did not get that first square correct, then I would be "off" when trying to square the block up leaving the 1/4" seam allowance from the intersection of the points. I got it now--thank you so much!!! Now I'll go off with both of your postings and play again with a sample square in a square in a square so that the process and what you both explained gets etched into my brain and muscle memory!

The center square would be half the size of the finished block plus seam allowance. The 4 triangles forming the on-point square are quarter-square triangles. The exact cutting size for those would be to cut a square the width of the center square plus 1-1/4", then cut diagonally in both directions to make 4 triangles. I would cut this square over-sized, adding at least 1-1/2" or more. Squaring up after adding these triangles is where the odd measurement comes into play. It's best to draw the block on graph paper to get this measurement. Or you could use Nancy's method. You could also get the measurement using the On-Point Ruler by Donna Lynn Thomas. Just measure for the finished block size on the outer edge of the ruler which includes the added seam allowance. The outer triangles are half-square triangles. The exact cutting measurement would be 2 squares cut half the width of the finished block plus 7/8", then cut in half diagonally. I would cut these oversized adding at least 1-1/4" then square to the finished block size plus seam allowance. For small block sizes I would definitely paper piece. The cutting would be the same, maybe adding a little extra if you prefer paper piecing with oversized pieces.

Hi Renata -

I haven't drafted this, but it's basic geometry. I'll do everything in finished sizes since that's easiest. Always remember to add your seam allowances.

So, if your outer block is 4" square finished, then you could think if dividing that into 4 2" half square triangles. The diagonal line of the half square triangle ends up being one of the edges of the inner square. So, the inner square is approx 2.83" (2" x 1.414 which is the square root of 2). You can do a little bit of rounding since fabric is a fluid medium, so you could go with a little over 2.75". If you really want precision, you could also go with paper-piecing this block.

Hope that helps!

ShariK wrote:
Shari,I agree that metric measurements allow for a little more precision--I grew up with metric and had to learn "inches" (inches were confusing for a while) and I do stick to metric for machine embroidery. But quilting seldom requires us to go to 5/16" so metric could become a headache too. Converting 5/16" to metric gives 7.9375 mm so you still have to approximate either to 7.94 or even 8 mm... still a pain to do... when I watched the video Julie Cefalu put together for this block, that gave me an easier way of figuring out where 5/16" was on my ruler.

A question for anyone who likes to draft their own blocks: this is the first time I've made a "square in a square in a square." I would assume that the first square in a square completed would be the size of the center of the outer square in a square. Is that a correct assumption? If so, or even if not, how do I figure out the size the very first inner square that I would add triangles to? In other words, how would you go about calculating the pieces for a"Square in a square in a square" (same as what Janet Stone made for her Letter "U")?

Thank you big-time in advance to any block drafters out there!

I did the block again, it worked. I think I couldn't get my mind wrapped around 5/16" I think Metric would be much more accurate. Since I've been doing embroidery and working with metric measurements I like using them.

Elizabeth7227 wrote:
Not quite, that would be 3/8ths. We want to be in between the 1/4" and the 3/8" line, where there is no line.

Gee, maybe we should go metric. Just kidding.

As we used to say in the picture framing business, 1/16" is just a "smidge" over or under 1/8".

Elizabeth7227 wrote: Well, actually halfway between 3 1/4 and 3 1/2 is 3 3/8....

" 5/16" is just 1/16" over 1/4" or

in other words, half way between 3 1/4 and 3 3/8.

Before you trim the unit, it should measure about 3 1/2", then it is trimmed to 3 5/16". 5/16" is just 1/16" over 1/4". Hope that helps!

Step 3 says to Trim the unit to 3 5/16" by trimming 1/4" away from the black points. Before trimming the block isn't 3 5/16 to start. I've double checked all my measurements twice. HELP