Rhonda K

Yes, you want to square up each unit that makes up the big block. It can be tedious but will give you the best results for a proper size block.

I just made a HST unit with a 4 inch square. Before squaring up, it was a little over 3 1/2 inches. Are you familiar with “squaring up” technique? Let us know if you need help. You want to “square” from the center seam out to the size needed.

Next question, did you perhaps pull from the 4 inch squares instead of the 4.5 inch squares? Easy to do.

I recently made some QST that didn’t come out correct. I upped the starting size and then trimmed down to size needed.

Barb in Louisiana

When I started piecing, I thought it was all about the 1/4" seam. But then I found out that if I had a full 1/4" seam, my blocks were too small. That's when I found out the object of piecing is to have what you have sewn come out to be the size you want. That meant I had to sew slightly less than a 1/4" seam. It is called a scant 1/4" seam. It is usually 1 or 2 threads into your 1/4" seam allowance. That made some of my seams way too small. That's when I realized that to cut the fabric out, I had to have the full fabric under the ruler line when I lined it up before cutting. Finally, you will save much time and heartache if you measure each section after you sew and press it. I love steam, but it did distort and shrink some of my blocks, so I just press with a dry iron. Good luck and enjoy your results. If your quilt doesn't look exactly like you wanted, there's a good chance no one, except another quilter, will know.

bearisgray

After sewing the units, you may need to adjust your cutting to your seam allowances - or vice-versa. with this block,it looks like all the units need to be the same size before assembling them.

cashs_mom

I was going to say the same. This method has helped me figure out a where my true 1/4" and my scant 1/4" is. I tend to use the scant 1/4" for most things. It seems to work best for me.

Polliwog

The pattern photo shows the unfinished size for the block. Usually most patterns note the finished size - meaning without seam allowances. That may be where you were initially led astray. I always think in terms of the finished size of a block. In this case, each unit finishes at 3". For the plain squares, cut 3 1/2" squares - no trimming necessary. For the half-square triangle units, first cut each fabric at 4", sew the diagonal seams 1/4' to each side of the diagonal, and then trim the proper cut size of the unit to 3 1/2". For the quarter-square triangles, first cut squares at 4 1/2" ( 1 1/2" beyond finished size), then sew the first diagonal seams 1/4" to each side of that diagonal (just like the half-squares aforementioned); then press seams to one side. Do not trim at this point. Then nest the seam allowances and cut from plain corner to plain corner, 1/4" on each side of the diagonal. Cut between those last two seams and press each seam allowance to one side. Now you are ready to trim these resulting squares to 3 1/2".

Quiltwoman44

and pressing your sewn seams open will also help a tad. Watch a lot of Utube beginner shows. Good luck.

joe'smom

Your correct seam allowance is the one that gets you the right size unit or block. I agree that you should check that by sewing pieces of fabric together and measuring the result, as in the video below. People get stuck on the idea of the 1/4", but if your seam allowance is a perfect 1/4" and your blocks are coming out the wrong size, that's not an accurate seam allowance.

https://www.youtube.com/watch?v=H_A1uPdqfsI

It takes time and practice to become accurate and consistent in your sewing, so don't be discouraged.

QuiltnLady1

When I make HST's (and QST's), in addition to washing and starching, I over cut my starting blocks so that I can square them up. The general rule of thumb I use is to make the square 1/4 to 1/2 inch bigger than the pattern calls for. I can then cut the sewn blocks down to size.

Starching is important (even if you don't prewash) because if the fabric is stiff it doesn't stretch as easily.

The classic way to check your seams is to prepare your scrap fabric the same way you do for your quilt (if possible, us the same fabrics you are using in the quilt), cut 3 2.5" squares and sew them together then measure your finished strip - it should be 6.5 inches. If it isn't, adjust your seam allowance accordingly and try again.

If you are not using super thin thread, the thread may be the reason the blocks are smaller and that is when you need to use a scant 1/4" seam. Also, one of the fabrics may be slightly thicker than the other and that will throw things off. As scant 1/4" seam means just a couple of threads smaller than 1/4". If you can adjust your needle a bit, that is the easiest way. I use a note card with lines in it (the lines are 1/4" apart) and I mark a

Blue Button

I see on the pattern it says the block is 15.5 inches UNFINISHED. I would think it should be 15 inches finished. You said it should be 15.5 finished, that would account for 1/2 inch.

quiltsfor

The 15.5" unfinished is the size of the block once you put all the smaller squares together to make the single large block.

The finished 15" measurement would be once the block is sewn to other blocks using each of the 4 edges/sides, (with exception to the blocks that are only sewn to other blocks on three sides - then that block would be 15.25 inches in one direction and 15" in the other direction. And then, adding the binding or putting on a border would cover that last .25" So when the quilt is completed, all the blocks should measure 15"