I always come up short...why?
 

When I do a rail fence or another very similar pattern....when I turn the block around (vertically ), I am always short. Do you know why this happens? Sorry that I cannot post picture (another puzzlement).....not a good start this morning:confused::confused:

I am guessing that you need to check your seam allowance. Here's a good reference:
http://www.quiltingboard.com/tutoria...ce-t89997.html

With a rail fence, if you sew long strips then cut, rather than using the measurement in the pattern to cut the squares, measure the width of your sewn strip set and use that to cut the squares. If your seams are off this will compensate.

Thanks for ur response. It is not the seam allowances.........there are only three pieces sewn together...each block is cut and sewn the same.....one goes horizontal and the other vertical....but when I turn the vertical one around to sew it to the horizontal one, it is always short....

It sounds like the problem is in your seam. Measure your finished strip -- If the center strip is not 1/2 inch less than your cut measurement and your outer strips are not 1/4 inch less than your cut strip, your seam is too large. Just readjust your seam. If that doesn't work, make sure you have cut all your pieces accurately.

Yep, it still sounds like the seam allowance is off. The horizontal side is just cut fabric with no seams, right, and the vertical side is the one with the seams? If your seams are just a tad too wide (easy enough to do), they use up too much fabric and leave your finished piece not wide enough.

I struggled with this for a long time. At times I even cut my pieces a few shades bigger, which helped, but made it hard to keep track of over the course of many pieces. Finally I adjusted my needle and guide to make me sew less than a quarter inch by a shade or two, and now my results are more accurate.

The long edge of the horizontal will stretch, the ends of the strips do not stretch hardly at all. Be very careful when pressing the strips and try not to press the edges, just the seams. Even holding the strips when sewing can stretch them. The last strip block I made I cut the strips lengthwise and had much better results.

If your sewing machine is like mine, it does not remember the way it was set up when it is turned off and I have to reset any settings each time I turn my machine back on. My needle goes back to the preset position and I have to remember this and move it back to where I have a scant 1/4 inch seam. I hope this helps, and I would also do what Bellaboo said, about pressing. Good luck.

you must cut them into squares. same size horizontal as vertical. then no problem will occur.

BINGO!!!! this way, if your seam width is not that accurate 1/4" you still get them cut in squares.

That being said ... it is vital that all the seam widths of all the stratas be exactly the same, so that all the tri-sets are the same width. Then once you have them all the same width, cut the squares at the same width/length.

My thoughts exactly.