I'm helping my adopted niece make a table runner for her family for Christmas. It will end up having 10-12 1/2 square triangles. I know that you add 7/8" to squares and sew on either side of the diagonal center line, but is that added to the end result of the squares or add on past the 1/4 " you normally have. I am cutting 2 1/2 " squares to end at 2 ". So do I cut 3 or 3 1/2 inch squares to make the triangles????
Any help would be appreciated----I told you would be shaking your head at me!

A lot of people make their hst units a smidge larger and then trim them down after pressing.

A rough formula - If you want a 3 inch finished square, cut the squares 4 inches - then there is a smidge to trim off - a "smidge" to me is less than 1/8 inch

x = finished size

so cut

x + 1 inch for the squares to be cut diagonally

the usual formula is to add 7/8" to the finished size - when I do that I always end up with a skimpy square - so I prefer to cut a tad (a tad is about 1/8 of an inch) larger and trim down after sewing

Good formula bearisgray :D I like having a little wiggle room with also :wink:

I like to think I cut and sew relatively accurately -

and when I'm sewing fabric that is "on grain" - I usually end up with something close to what I'm aiming for.

For the life of me - when I use that plus 7/8 inch and sew with my "usual" seam allowances, those doggone finished squares are ALWAYS skimpy.

So - even though it takes longer, it saves me aggravation and fabric in the long run to cut with the plus one inch and neaten up the units after sewing and pressing.

I haven't done the starching/sizing - maybe that would help?

thank you sew much!!

Bear, I'm not the greatest sewer, that is for sure but I starch the bijesus out of my pieces and I still can't get a stupid 1/2 square to come out right when I do the 7/8 thing. My fall blocks all have really "scant" 1/4 seams for just this reason!

Not only do my blocks come up skimpy with the 7/8 added, I find 7/8 a pain in the behind to read on the ruler. A nice 1 inch is so much easier for me.

Thanks. That makes it easier for me.

I had problems with HST and tried many methods even the fabric sheets preprinted with the lines to sew.
But I finally found the method for me. It is the Quilt in a Day way.
If you get the triangle square up ruler it has all the sizes and the square up lines that you only have to cut one time to square up. It is fast and easy with just a scant of fabric to cut off. Mainly you get perfect HST and you get 8 at a time.
Try it out for 2 1/2 inch Hst. Cut out 2 six inch squares and place them right sides togather. Then draw and x and sew 1/4 inch on each side of lines. Cut the square in half on both sides + . Keep the square togather and cut on the drawn lines. You will have 8 - 2 1/2 triangles. You can square up as usual but with the ruler you only make one cut. The ruler is place just above the stitch line and lined up on one side then you cut off the one edge and you can cut the tails at the same time. Press and you are done. 8 at a time and all perfect.
http://quiltinaday.com

What at great idea! I'll have to try that one. Thanks