I am making a table runner. The middle square needs to be 9 1/2 inches (which includes the 1/4 inch seams.---so finished, it will be 9 inches). I am choosing to make that middle square in a pinwheel. I have made 3 samples and used every ratio that I can remember and this darn square just does not turn out to be 9 1/2 ".
A friend said that there is a magic formula for pinwheels---I cannot find this formula anywhere online..
This shouldn't be that difficult. What am I doing wrong? Is there a formula to make this easier? This is a simple table runner and the comment was that I should be able to complete it while my cup of tea cools down. So far I have spent 2 days on this square and can't get it right---ugh!
Thank you for any help that you can provide.

Craftyquilter posted this url.

http://www.waukinvnetcorp.com/myquiltgenie/mgq_hst.php

I think the "magic" is to make your half square triangles from squares that are N and 7/8th inches. For example, 4 and 7/8th.

Do a search on half square triangles and pinwheels, too. Lots of info posted.

I just drew on up on my eq7 and it gives measurements at 5 5/8 inch squares.....

and it isn't a bad idea to make your squares a bit bigger and then you can square it up to exactly 9.5

5 3/8" squares will make your hst.

Here is a tutorial for you:
http://www.connectingthreads.com/tut..._HSTs__D4.html

Or if you doing a pinwheel like the one from Quilter's Cache with 3 fabrics, it would be
5 3/8" for the half square triangles
and 5 3/4" for the quarter square triangles.

Is this what you need?

Jan in VA

Jan has the best suggestions -- trim each quarter before assembling into the pinwheel.

I made a couple of samples to be sure I really knew what I was talking about when I said 5 3/8". They aren't perfect, but it is almost midnight and I am tired.
The hst's in the first block were made with 5 3/8" squares. The block measures 9 1/2", so it would be a 9" finished block...
For the second block I used 5 3/4" squares to make the hst. You would have to square these alot to make a 9" finished block...

I did try your method, Jan, but the pinwheel shrunk much more than I had expected. I also tried the Missouri Star Quilt Co. you-tube idea (so much easier)

http://www.youtube.com/watch?v=ekYpJzHoW6E

but still could not get the dimensions correct.
I watched the tutorial and this makes perfect sense...and it does have that "formula" that my friend was talking about.
Thank you all so much...I will try this today. I want to get this thing started,,,maybe even ready to quilt TODAY!

tellabella, what is the EQ7 that is mentioned? I am assuming that it must be some computer thing?? Can you tell that I am a newbie?? lol

what a wonderful bunch of quilters!! Not only do you give answers, you even show samples. And Jan, I wish you lived next door!!