bearisgray

There are so many OTHER variables to consider besides the seam width.

When I cut my strips, for example, they are actually about 2 -17/32 wide instead of 1-16/32 inches wide. Ruler placement on the fabric can affect how wide the strips are.

I get 'a bit bigger' when I go around a template. If my template is 4 x 4, and I cut around four sides of it, my piece will probably be close to 4-1/16 x 4-1/16. So if I use a 'regular' quarter inch seam, I'm okay.

I haven't checked the actual width of the strips using the June Tailor shape cutter, so I don't know how they come out.

So a good place to start with 'where is the problem?' is with the actual width of the component (strip, square, whatever)

If you use pre-cuts, they are probably 2.5 inches instead of a 'bit' more.

Some fabrics are bulkier than others.

Some threads are bulkier than others.

So there is MORE than just the seam width to consider when trying for a certain sized finished block/unit.

The 'sewing test strips' is really worth the time and effort!

You know how some people think that if one glass of wine is good, two will be better?
I think some people think that if a 'true' 1/4 inch seam is good, a 5/16 inch seam will be better.

The difference - to me - is about 1/64th of an inch. (or as some said, one or two threads)