I am trying to make a very simple log cabin lap throw using the pattern from Nancy Zieman's Book, Quilt With Confidence. The block calls for a 4 1/2" center and each log is 2 1/2". There are two rows of dark fabric and two rows of lighter fabric. The finished size is "supposed" to be 12 1/2" but hard as I try I just can't get that to happen. Now my question is, how much would I have to add to the center piece and each of the rows in order to get a 12 1/2" finished block after I squared up the block. It just seems like I can get a finished 12 1/2" block by squaring it up to the size rather than trying to cut and sew together so that when I am finished I have a 12 1/2" block. I just finished one and all of the blocks are just slightly off but in order to square up the block I need to take it down to a finished 12" block when I would really rather have a 12 1/2" block.

Don't even bother. Make all the blocks and then trim then down to the size of the smallest one. That way they'll join together easily.

Then, when you're done, take a look at the process again. The directions are correct, and should result in a 12.5" block.
But the blocks are off because something isn't right in the way you're cutting, sewing or pressing (or all or any combination of the three).

The log cabin block is very forgiving, and since those logs are wide anyway, it will not be noticeable.

You need the blocks all to be the same size more than you need enlarge them to come out to 12.5" (for this quilt).

Here's some more info:
http://www.quiltingboard.com/t-112724-1.htm#2925138
The part where I recommend Sally Collins' book, The Art of Machine Piecing. It's the bible.

Sounds like you have been visited by the "scant" ghost. the sizes you cite "should" give you the 12.5 block, the finished size of the center is 4, then add two 2inch dark and two 2 inch light for a total of 12 inches with the outside seam allowance still in position for a total of 12.5 inches. Try re-sewing the block with a seam allowance of slightly less than the quarter inch you are typically using. That's called a "scant" quarter inch. Measure each step to ensure you are staying true to the correct size. Are you using a quarter inch foot? If so, keep the edge of the fabric just shy of the quarter inch mark on the foot so you know you are "scant". I wouldn't add to the center, just try to resize my seams. Hope that helps!

Sounds like you have been visited by the "scant" ghost. the sizes you cite "should" give you the 12.5 block, the finished size of the center is 4, then add two 2inch dark and two 2 inch light for a total of 12 inches with the outside seam allowance still in position for a total of 12.5 inches. Try re-sewing the block with a seam allowance of slightly less than the quarter inch you are typically using. That's called a "scant" quarter inch. Measure each step to ensure you are staying true to the correct size. Are you using a quarter inch foot? If so, keep the edge of the fabric just shy of the quarter inch mark on the foot so you know you are "scant". I wouldn't add to the center, just try to resize my seams. Hope that helps!

I agree with MTS, but if you're not in a rush you should try and figure out why it's not coming out 12 1/2".

Start with the cutting and make sure you are getting accurate strip widths. One famous quilter (I think it's Jinny Beyer) suggests always cutting one thread larger than the measurement.

Have you checked to see if your 1/4" seam is actually a true 1/4"? Your foot or needle may need to be adjusted to get the accuracy you need.

What size is your block coming out? Is it 12 1/2" in any direction?

Hope this helps!

Blackberry,
The log cabin is one of my favorite classes to teach and I make many of them myself; the block is incredibly versatile.

I square up LC blocks after every "round"....that is, after 4 sides of the center block have been sewn. (I call it four logs being added to make the house square.)

I use a square up ruler, and with the center square (also known as the hearth block) exactly in the middle, I trim tiny amounts off EACH side of the cabin to make it square.

Make note of the measurement the first time you do this, and use it on every LC block at this point. (You may not make all the blocks in one sitting, but you will be able to trim later ones to the same size if you make a note.)

Then I trim again after the next complete "round" of 4 logs added. And again if there is a third "round".

When my blocks have all been made and trimmed, the size they are after the final round is the size they will be for the quilt. To me it doesn't matter if they are the exact size the pattern called for as long as they are all the same size as each other. :idea: Everyone's seam allowance will be slightly different any way; yours is your own Personal Private Measurement. The blocks will be close enough to the size called for in the pattern that it will make a quilt pretty close to the finished size the pattern stated. :D

**Disclaimer: This method of letting the size fall where it may will likely only work for you if you have a quilt with JUST LC blocks in it. If there are other kinds of pieced blocks among the LC blocks, then you'll have to worry about making them all exactly the same size in order to fit together.**


Jan in VA

I must not be sewing or pressing them correctly because in the squaring process usually the amount at the top and bottom of the block that I have to trim is a little larger than in the middle. I think all of the strips were cut correctly. I was doing this using the strip piecing method but I am wondering if maybe it would be better if I just cut each log the size it is supposed to be and sew it together. I also think that squaring up after each row, like Jan suggested, would probably be a good idea. More work but probably worth it in the long run.

I whole heartily agree.


If it is strictly a sewing error, spread across the five seams, each seam is sewn only1/20” from where it should have been sewn. That’s a very easy error to make - one we have all made.

I use this same cutting technique. If you have Omni ruler, don't line up the cut edge of the fabric on the tiny black line. Move it to the outside yellow line (located on both sides of the tiny black line). NOBODY tells you that you lose a little bit of fabric when pressing a seam to the side. That is why there is so much talk about a scant 1/4' seam. My friend showed me this trick (I wish I could show you) and it resolved my shortage. By lining it up to the yellow line instead, you are just cutting your strips just a thickness of a pin. But you have to find out how accurate your seams are too. Many ways to correct that problem. I always find that being consistence is best. You can always add a bit more fabric in your borders to make up for any slight lost on the size of your quilt. It is so IMPORTANT to get joy out of what you have made !! GOOD LUCK !! :mrgreen:

I can't make a log cabin come out to the right size or straight to save my soul! The only way I have gotten it to work is to paper piece it. All the lines are straight and the size is exact.