Sashing can correct a lot of errors. One LQS owner showed me how to sew sashing on the right side of a block, then on the bottom of the block then square it up. Do this instead of sewing sashing all the way across a row. This came in handy one time when I was asked to put blocks together that each block was sewn by a different quilter. It was a shock to see what a difference there was in seam allowances. The blocks were suppose to be 12 1/2" unfinished. Well, very few were. The blocks were anywhere from 11 1/4" to 15" (?). I had to trim down on several of them before putting sashing on like the 15" block.

I just did a tumbler quilt where I used a 3/8" seam allowance so that when I quilt 1/4" from seam, I will catch the seam allowance in it. Had no trouble putting the blocks together since they were not intricate piecing and all that mattered was consistency.

Also wanted to add that I like to over size the smaller blocks than square them up. Like making half-square triangles. To Make a 3 1/2" unfinished, I will cut squares at 4" rather than at 3 7/8". As I get older it's awfully hard to cut anything using the 7/8" line.

Accurate enough that any inaccuracy cannot be seen by a rider on a galloping horse! froggyintexas

I was replying to QuiltinNan's post about doing a double seam on thinner than desirable seam allowances. It's obvious if you read posts in threaded mode. Sorry you were confused.

I tend to reply like i'm in a conversation. I will make an effort to be more clear ;-)

I try to be pretty accurate, however I have vision problems so I just do the best I can and I don't stress about it. If quilting isn't fun any more I will do some other craft.

When do you use a scant 1/4" and when to use 1/4"? What is considered a thin thread? Does everyone use a different bobbin thread then top thread?

I have found thorough trial and error that thread size does affect the seam allowance. So I try to use the same thread throughout the piecing. With "So Fine" from Superior Threads, my seams are more true to 1/4" . With Connecting threads thread, I have to allow almost 1/16" to account for the width of the thread. Finished block size, I like to stay within 1/8" of what it's supposed to be, and I try ( notice I said TRY) to be extremely accurate when star points are right on the seam line. If they aren't quite to the seam line, I can live with it, but if they are chopped off, it really bothers me.

Tartan... thank you for showing that foot! I didn't realize the fact about the notch... very helpful! All these comments have been helpful... I am not a particularly accurate "seamer"... but I want to be better... every suggestion helps!! I DO enjoy the process, but want to get better...

I am OCD about my seams; I work as accurately as I can and then trim as needed. I don't to rip seams.

The importance of accuracy will show the most when you start putting blocks together. If your seams don't match up, there is a problem somewhere. If ALL your seams are the same little "one thread" off, they will match up exactly but your quilt may be a little smaller or larger when finished.