Rail fence with pinwheel question.
 

Hi, I wanting to make the rail fence with pin wheel quilt. My pattern is for the rails to be 2 1\2 inches. This will be a scrappy quilt and I need the rails to be 2" (already have these in stash). My question is what size to cut the half square triangles? Thanks for your help. Pat

Are you doing a rail block & pinwheels blocks? What size would your rail block be? Or what size would your strips measure out to in your rail block?

Seems to me that the pinwheel portion is 2 rails wide? Is that right?
Each 2" rail will finish at 1.5", so each HST patch of the pinwheel will finish at 1.5" (the entire pinwheel will be 3" finished) So you add 7/8" to the finished size of 1.5", which comes to 2 3/8". Since we want a little wiggle room, round up to 2.5", sew your HST and trim.
Make a sample to double check!

Agree with Paper Princess and her math.

If your rails are 2-1/2" cut, 2" finished, then use 2-1/2" cut squares and sew them to the rail, through the center of the square. Similarly, 2" cut rails finishing at 1-1/2" would use 2" cut squares.

I wouldn't bother with doing HST's here, It will make you nutty.

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This block would be done by sewing the squares/triangles to the last row, then assembling the rail units, then sewing those together into the 4-patch.

Here are free patterns for two versions: http://colormequilted.com/favorite-patterns/

Those are the exact two patterns I made for myself. Funny!

Her finished rail (if using 3) would be 6" or 8" if using 4