On point blocks -- what size do I make border triangles?
 

I'm sure that you nice people have discussed this before but not being a computer person, I can find no reference to this here...

I'm making a quilt for my GD. I want to put the blocks on point. What size do I make the squares to cut into triangles? The quilt squares are 12 1/2" unfinished. So do I cut a block 12 1/2" to have 2 triangles for the edges? Or do I need to make the square bigger?

Does this make sense at all???????????

Here is a website that addresses the math:

http://www.quiltbug.com/Articles/on-point.htm

Thanks for posting the link. I was just getting to this problem myself.

Thanks so much for the link....I was REALLY scratching my head over this math problem....lol

the trick is to remember that those triangle should have the straight of grain on the outside of each corner... you do NOT want the bias edge to be on the outside of the block... so the diagonal must be the same size as the square you want to sew it to... the easiest way to get these is not to cut triangles, but to find the right size square (above site will help) and then cut 2 squares that size, slice both in half diagonally and then 'deal' them around the block like cards... the size you need is 13 (half inch for trimming) times .707.... it will be a smaller square than your block because the diagonal of a sq is larger than the square... sew all 4 corners on and then square up...

if need be, before you move your cut side triangles and corner ones, put pins in one side to keep straight where they get sewn. i have a 20 inch ruler that has the cutting triangle measurements on it for each square/block size you make.

I like to cut the triangles larger than necessary, sew on to the border, then trim to size.