What size do I make my squares and how do I figure it out?
 

I want to try the HST by cutting squares and sewing 1/4" around the whole outside and then cutting it into 4 pieces. But I don't know how big to make my squares. If they are 2 1/2" trianges I'm making, how big are the squares suppose to be? And how much do you add to the 2 1/2" to get the right size? I hope someone can help me figure this out. I really want to try it.​

well do a pratcice piece start with a 6.5 inch square then you can always make the square smaller and do another til you get what you want

This tutorial has a chart with different sizes http://whipup.net/2011/03/17/guest-b...are-triangles/

I will defer to the experts, but I don't think you want to cut a square into fourths to make HST's. It leaves two on-the-bias edges on the outside. Very unstable. Maybe that's why you sew around the edge?

cutting into 4 makes 1/4 square triangles- not half square triangles. and doing it that way gives you 2 bias edges to deal with which makes very unstable blocks to work with- there are much better ways to make these-
1/2 square triangles you cut your squares- put two together- draw a diagonal line- stitch 1/4" on each side of the line- then cut on the line for (2) 1/2 square triangle blocks.

I know it leaves the edges on the bias, but I can be really careful. Thanks for the site Hemlock Tea. It's perfect!! Just what I needed.

For 8 hst's the rule is: size desired x 2 + 1
Examples: need 2" hst: 2 x 2 = 4 + 1 = 5" square
need 3" hst: 3 x 2 = 6 + 1 = 7" square

I have tried this method and it works great. Thanks for the chart.

For 8 HSTs draw an x and sew 1/4 in from lines. Cut in half both ways then on lines. No bias edges.
I use 6 in squares for 2 1/2 in triangles. You do need to square up a little.