H Wilma I can't anwser your quistion as I havent started quilting yet. but welcome from Oregon.

Do your pieces measure correctly to start? Is your 1/4" seam a full 1/4" or scant? Lastly, what has already been mentioned, how carefully do you press? If each one of those is off a hair, it all adds up. Don't give up - I think we all went through this (and still do sometimes),

Hi, welcome from Louisiana. Iam new to the board
and new to quilting but having lots of fun.

Greetings from South Carolina

Hi Wilma...welcome!
Just did a quick search on the Board for mock stack and whack...I wasn't familiar with the block. If that's the block you're making, then I'd guess that the center seam is creating your problem of one side good and one side too shy.
One side being half a square diagonally...right? This is very likely a pressing issue...revisit the direction you've pushed the seam allowances...if you are unable to "pinwheel" that 4 patch type center, you might want to press open those seams and or try that aggressive technique that requires you press till hot and then whack it with a hammer to flatten that sucker! lol Seriously, tailors and seamstresses have used hammers forever. Now aren't you glad you joined...on a Friday during the Winter Olympics in February during one of the strangest winters we've had in recent memory? I think I'll stop now...I have tears in my eyes and my sides hurt...please tell me that you are laughing... with me...I hope. You're really going to love it here...I promise that I'm usually way better than this or quiet...quiet might have been the better option tonight!
Good Luck!

Welcome to the board!

Hi and Welcome from Oklahoma.

Sounds like your not getting a 1/4 seam allowance during sewing? A scant 1/4 ' should get you what you want. The trouble came after you started sewing right? if your seams are even slightly off your final result will be too.

thanks everyone for your tips i am going to keep trying until i get it right, i am not a quiter i will rip and sew and press until i get it right.

Hi Wilma. I am wondering if your cutting lines are all exactly the same. If each one of your pieces is exactly the same size you shouldn't be having that problem. Stack them on top of each other and see if they all measure exactly the same size. Sometimes mine get off a little and that does make a huge difference but not unsurmountable. We aren't doing rocket science so if they get off a little and it's unnoticable I just keep going, as long as your blocks are the same size. Also I usually do smaller than 1/4 inch seams on any kaleidoscopes because of the bulk. And make sure you are pressing and not ironing. Hope this helps.