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.