1/4" or scant 1/4" - what do you prefer?
 

Do you measure at the stitch line or after? Do you steam shrink your block if it is slightly larger? Do you find different brands, weight (50 or 60) thread makes a difference whether you use a 1/4" or scant 1/4"?

I use good quality serging thread which creates less bunk and the result is a perfect 1/4" seam with the Bernina #57 foot. However, when I use regular 50 weight thread I use a scant 1/4" which is accomplished by moving the needle one notch to the right using the #57 Bernina foot.

I always use a scant and even that varies as to how much I move the needle. Some patterns have more pieces in a block than others and need more needle movement.
I have never used a full 1/4 in as my blocks will be too small. It is tricky and sometimes but rarely my blocks will be too big.
I dont really worry about the size of blocks except when My group needs a certain size block then it has to be perfect.
If it is just for a quilt Im making then blocks can be any size as long as they are consistant.

It isn't the measurement of the seam that is the important thing, it is the measurement of the pieces you are sewing together. You want to press your seam then measure the sewn piece minus 1/2 inch (which is 1/4 inch from each piece) That should be the measurement that you are concerned with. Depending on your fabric, thread (and location of the moon and stars!!) your sewn seam can vary.

I move my needle over to the third position from the right, (on my Bernina) it measures a 1/4 seam.
I'm not sure it really matters as long as you are consistant throughout the quilt.

I measure the 1/4" from the needle to the plate and put a barrier to guide my pieces with. After I have the barrier guide in place, I move my needle one click to the right.

I have a regular sewing machine nothing fancy. I can't move my needle. Basic sears. I line my fabric against the foot and the plate shows 1/4. I just follow that line. I of course am not as experienced as others, and just stick with 1/4 inch. I suppose it's preference, or if your following a pattern.

I know that the thread you use does make a difference. I was having problems with a standard 1/4 seam but started using Aurofil (sp?) and it did make the right size blocks. However, I have lots of thread I want to use and so since it's bigger I now use a scant 1/4 and it works great. My Viking has a 1/4 inch setting, guess what- it's a scant 1/4. Guess 15 years ago Viking decided it made a difference. Wow.

That is what matters--beconsisten in your quilt. When it comes to borders don't go by the pattern. Do your own measuring by laying the borders on the quilt and checking size.

I use "my" 1/4 on blocks that will all be made by me and used for a single quilt. That way they will all be the same and no one else has to work with them (e.g., I might end up with all 12 1/4 inch blocks). But for a block swap, I use a scant 1/4 inch to make the block mathematically exact (like when it should be 12 1/2 inches) - that way makes it much better for another to use the blocks.

Why don't I use the scant all of the time? Because I have to make a manual adjustment to my machine every time I turn it on and it's easier to just use the foot guide and not adjust unless I have to!

I use the 1/4" all the way till I'm done.