help with half square triangles
 

I have a pattern that tells me to cut 7x7 inch squares then to cut down to 61/2 squares for half square triangles what is the atvantage of doing it that way verus cutting it to 61/2 to begin with any help is greatly appreciated

Cutting down your HSTs is done to be sure you have a full seam allowance and accurate 6.5 inch squares when complete. It also gives you a bit of wiggle room if your line of sewing isn't completely straight...say the last 1/2 inch of your 7x7 seam is a little wonky, you can avoid redoing the block or seam ripping by cutting the wonky part off.

There are many ways to do HSTs, if you aren't happy with this one, use your method of choice. As long as you've got the 6.5 inch completed square, how you go about getting there is personal preference. I hope that helps.

I would probably try cutting a few 6.5 inch squares, make the HST and see how they work. If they do, stay with that, if not you can always follow the instructions with the rest of the squares. I would hate wasting the material.

If you start with 7" squares ... sew the two diagonal lines and cut apart ... you have two HSTs that are NOT 7" squares. You lose size with the seams.

You will have very little to trim off to make them into tidy 6-1/2" HSTs.

The rule of thumb is you cut your starting squares 7/8" larger than the finished size of the HSTs you want. Those 6-1/2" HSTs are going to finish at 6" once sewn into place, so the extra 1/8" just helps give you perfection!

Yep. What QuiltE said. To get afinished 6" square (raw 6.5") made from 2 triangles, you need to cut the squares 6 7/8". That extra 1/8" is your safety blanket. If you don't use that elusive scant 1/4" seam, you need that 1/8"

they simply are making it simplier, instead of adding 7/8 of an inch and sewing and hoping they come out square, they have you add one inch and sew and trim a tiny bit off. that gives room for mistakes in sewing. if you are good, just add 7/8 and go for it.

The bonus ... you can make your HSTs truly square ... and it'll help improve your finished project!!