I have never heard this. Sounds like I need to overhaul my ruler collection.

A few years ago, a teacher in a quilt class told us it doesn't matter which tool you use to measure in a project, but that we should use the same one throughout. I have done it like then without really thinking of why. Makes perfect sense.

Yes you are very right the width of the lines makes a huge diff x's how many seams in a block...

It is just like the 1/4 in seam and the scant 1/4 th in seam x's how many seams.

The better the fabric and or the heaver the fabris the scant seam works best... just think 4 thickness of fabric + the thread.

Test on diff weigth's of fab and press the seam out and measure.... you realy will be surprised.

Sometimes it is just those few extra or less threads in a seam x's how many seams.

I did not know this, luckily I only own one ruler for quilting. Thanks for mentioning this

I found out the hard way about switching brands of rulers. I switched half way through a project after realizing that I could mark and cut more simply with another ruler. My 2 sets of blocks came out a full 1/2 inch different. More unsewing...

What a nuisance. they should all be the same. I sometimes wonder if they are even straight

Thanks for the tip. I'll have to keep it in mind when I go looking to spend my gift card.

I found this out the hard way when a group of us were sewing friendship star blocks. Each of us had our own machine. We started out assembly line style , but having more than 1 person working on the same block was a disaster.
Then we switched to each one making a full block at a time. That worked a lot better. We didn't have to sew the star blocks together or we would have had the same problem again.
Amazing how fussy our craft can be, but then, we aim for perfection don't we. But if you aim low - you won't achieve higher. :)

Good to know, I will watch that from now on. Thanks!