I have just sewn a railway (ish) block and the strips i have used is 2,5 and i thought i was then making each part 6 by 6(well thats what i have done now

all 4 parts are now sewn together and the finshed square are about 11.5 is that right or what have i done wrong??? :oops:

you sewed three 2.5 x 6 inch strips together and that made a 6 x 6 unit?

if that's what you did, you "lost" a half inch in the seam allowances - so at this point, your four-unit square should measure 11.5 inches

after those units are sewn together, they will "finish" at 11 inches

if all your units are ending up the same size, it should go together just fine

do you use commas or periods/dots when you separate the whole number from the decimal part of a number?

I get so confused when people say "finished" or "unfinished" size - to me, "finished" is the amount that would show after the blocks are sewn together - "unfinished" is the size of the block before it's put into the top

12.5 unfinished will be 12.0 inches "finished" size

I think that if you sewed three 2.5in strips together with quarter inch seams, your little block shoud have measured 6.5in. You must be taking larger seams. When you look at that little block, from the front, finished, the first strip should measure 2.25in, the middle strip 2in, and the other edge strip 2.25in. , total 6.5in.
If you have four 6.5in blocks sewn together, then the completed block should then measure 12.5in square.

you are correct. my math was WAY off this morning. Those strips FINISH to 6 inches wide. (nothing like a public error to keep one humble :oops: )

How long did you cut your sewn together strips?

well the 4 i have sewn together is 11.5 of some reason.

but i checked my ruler and its 6,5 not 6 as i thought :oops:

When I did this first at a class, the instructor had us measure several different spots on the strip set and take the narrowest measurement. For instance if your strip set measured 6" in two places and 6 1/2" in another spot and maybe 5 3/4" in the narrowest spot, then we were to cut then strip set into 5 3/4" squares. What I always found was that my 6" strip sets were never that far off, just generally a scant amt...but I was always careful to use the lesser measurement to cut my squares. I imagine this is about as clear as mud, isn't it? Sorry, but it does make sense once you have done it.

if the blocks are for a quilt you are totally making - continue as you are. If they are for a swap adjust your seams to a true 1/4" and I bet they turn out to size.
good luck with these

if the block is laying flat and they are going together okay - go for it - if it's lumpy or puckery, you might want to figure out what the problem is