I was suppose to be making a 12 1/2" block unfinished, but after the 3rd try it's still a 1/4" short. Would a scant 1/4" work? I'm almost ready to give up.

I've even done 1/8" with a short stitch length!

Check ruler for accuracy, use smaller gauge thread (2 ply its best), and yes, remember the scant 1/4" seam.
Good luck

If the pattern for the block you used is from Quilters Cache, you have to use a scant 1/4". Ask how I know.

what block are you doing?

or cut your pieces just a little larger and trim to size as you go....and check your 1/4" seams- being just an itty=bitty 1/8" off adds up quick- two seams off by 1/8" makes you a 1/4" after 2 seams- a wopping 1/2" with just 4 seams...they add up -- 8 seams and you are a whole inch off!

I doing the Perpetual Motion block from DelawareQuilts.com. I'm even marking the 1/4" seam and it still doesn't help. I'll have to check the ruler I'm using.

Move your needle over to the right just a hair so you're one thread to the inside of that 1/4" seam allowance.

Can you do them all that size?

Yes, do the scant seam. Have you measured the seam?

My mom is having the same problem, only we did cut it bigger and it was still too small. something about 12.5" blocks... they just dont like her.