Need help on 1/2 Square Triangle size
 

I have a quilt I am trying to make. I have 5 inch squares of my main color already cut. They were given to me. I want to make a quilt with 1/2 square triangle in it can someone tell me the size to cut the squares to make the 1/2 square triangle's so they turn out 5 inches?? I know I have seen it and I thought I saved it so I could understand but I can not find it. Thanks so much I love this board I don't post often but I sure learn a lot

This chart says 7" http://whipup.net/2011/03/17/guest-b...are-triangles/

1/2 bias squares
 

I think you forgot to figure in the seam allowance for the center of the block. For a 5" block you need to start with a 5 7/8" square. Then cut on the diagonal. When the pieces are sewn together, they will measure 5 1/2" and when they are set in the block they will measure 5" square.

Hope This Helps

sucia

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Sorry but you can not make this a 5" finished block. You always need to make the block bigger by 7/8" since you are sewing and cutting on the diaginal. IMH you should cut the squares 4 7/8", Draw a line diaginally on the square, sew 1/4" on each side of the line and cut between the stitching . This will give you a 4 1/2" square or 4" finished. Even if you decide not to do 1/2sq triangles the largest size block you will get is 4 1/2 due to seam allowance. You did say that the block were already cut. Sorry you can not stretch the block to be bigger!

If your solid blocks are already cut to 5 inches then they will finish to 4 1/2".
I would cut the blocks for the 1/2 square triangles at 6", cut on the diagonal and sew the two new triangles together, press and trim to 5". When sewn to another block they will finish to 4 1/2".

[QUOTE=bigsister63;5767553]OK. I am assuming here that you are not going to use any of the 5" squares to make the HSTs. You have (at least) 2 other fabrics that you are working with. Is this correct?

If this is the case, bigsister63 is partially correct. The squares already cut are 5". They will finish at 4.5", so that's the size you use in the calculation. So now I'm going to give you another number!
You add 7/8" to the FINISHED size to get the dimension to cut the starting squares.
So, 4 1/2 + 7/8 = 5 3/8. Since we are not big on eighths, round up.
Cut the squares 5.5 inches. Draw a diagonal line, corner to corner on the back of one square. Place this, right side together with your other color. Sew a scant 1/4 seam on each side of the line. Cut on the line. Press. Trim resultant square to 5".

If I have not understood you correctly, and you are going to use the 5" squares to make the HST, then, after sewing, you would trim to 4.5" and they would finish at 4".

This is what I was looking for. I want to use the 5 inch blocks This lady gave me a bunch of stuff and I want to make her a small quilt as a thank you. I remembered someone saying the 7/8th but just couldn't get my head around it I will cut them 6 inches and trim down Thank you

I just realized how confusing this is. I want to use the 5 inch squares as squares and cut others to go with them and wanted to know how big to cut the squares so when I sewed the triangles they would be 5 inches

It's amazing how many answers you have so far. :eek:

I agree with PaperPrincess - if you want HST's that finish at 4.5" to go with the 5" unfinished squares, add 7/8" to the finished block size of 4.5", giving 5 3/8". Many quilters will add an extra 1/8" (giving 5.5") and trim the HST slightly after sewing.

I have a Fons and Porter Half and Quarter ruler. To be sure I knew what I was talking about I just went to my sewing room and took two 3" squares (because they were handy) and using the ruler made a half square triangle which measures 3 inches square when finished!! The only thing is.....the ruler is just marked up to 4 inches, but it would be very easy to figure the 5 inch line and mark it with a piece of painter's tape, etc. I use this ruler a lot. You can take a 2 1/2 inch jelly roll and using this ruler make 2 1/2" HST.