lynnie

I always cut larger and trim down. an inch will give you more than enough to do the trim down method.

ManiacQuilter2

Yep, it is 7/8" I was putting some squares on point which were a strange finished size of 2.125" So I guessed that a square cut in half of 2.75" would work. It was short just like yours. 3" square cut in half worked perfectly. I usually round up to an inch and then trim. I have never made anything with an 1/8" inch but I am once again making Bibles bags for our missionaries going to the Philippines later this fall again.

bearisgray

these drawings might help explain what happened -

(Sorry about the poor quality - I have a new scanner and am still learning how to operate it)

Basically, what happens:

When one cuts a square - one cuts it 1/2 inch larger in both directions that the finished size to allow for seam allowances.

When one cuts a square diagonally to make half-square triangles - the points add an additional 3/8 inch to the 1/2 inch seam allowance of the original square - so that is why one adds 7/8 inch (one inch usually works better - and just trim a smidge from the sewn unit) to a square that will be cut diagonally to make HSTs.

coopah

Those pesky triangles! The cut larger, trim down method is the only way I can get them to play well with the rest of the pieces.

Vat

Another way to help control those bias it to starch your fabrics before you cut them out. I use Sta-Flo (buy at Walmart) mix with half water. Spray your fabrics thoroughly with the starch, I allow mine to air dry and then
press. Big difference. I do this with ALL my projects.

madamekelly

7/8" is correct, but for me, I just add an inch to the square that will be cut diagonal, sew it to the square and trim to size. Perfect every time. If you have everything all cut, just make the square that will not be cut a little smaller should also work. Good luck.