Let’s say you are making a quilt with 4″ square blocks that are all turned on point. The main block is easy, you just add 1/2″ to the finished size, so you cut them at 4 1/2″.
Then you have to decide what size the triangles on the sides and corners should be. You would start again with the finished size of the main blocks and for the side setting triangles you add 7/8″ to that measurement and slice the blocks in half diagonally.
For the 4 corner triangles you add 1 1/4″ to the 4″ so the block to cut is 5 1/4″. You then slice that block twice from corner to corner to get the 4 corner triangles.
If you like, you can also add a little bit more and trim the blocks later, or you could leave a little bit of extra fabric above the points to float the blocks.
If you need more information I highly recommend and article posted by Robin Strobel. The link is:
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