Tutorial: diagonal rail fence

Here's how to make diagonal rail fence blocks, like those in Isaac's quilt that I showed you last week, with zero waste.  I think this method is especially nice for plaids, but if you don't have a lot of plaid in your stash, try out other fabric palettes.  Basically you stack up a pile of blocks, cut through them all in one diagonal line, then switch the order so when you sew them together you get two-tone blocks.  Like this:

Make a diagonal cut through the whole stack.  Take the top piece from one of the piles and put it on the bottom.  Now sew the pairs together in their new order.

You get three new blocks, all different.

Depending on how close to the top edge you made your first cut, and how skinny you want your rails to be, you may have room for as many as three or four more cuts.  Or you may want to quit after one more cut, giving you three rails in the block.

You always do just one cut at a time, swap the pieces and sew the new pairs back together.  That way you can't lose your place or sew the wrong pieces together.

After you cut, always make sure you take the top piece from one of the piles and put it on the bottom so the new pairs will join different fabrics.

This is the basic recipe for making three blocks.  If you want four blocks, start with four pieces of fabric.  Five pieces of fabric will give you five blocks.  This rule holds true no matter how many cuts you make in the blocks.

If you want nine blocks in your quilt, you can make three sets of three, or a set of four plus a set of five.  You can even rearrange the piles in midstream.  For instance, make one cut in a set of four blocks, and one cut in a set of five blocks.  Sew them back together.  Now take two blocks from one set and swap them out for two blocks from the other set.  Stack the blocks and proceed with your next cut.  If you like math puzzles, you can write algorithms for complicated mix-and-match procedures that will give you many no-two-alike blocks.

Three pieces of advice:
1.  Never ever switch the direction of the diagonal cuts in the same block.  If you make some cuts slope up and others slope down, the blocks will look really crappy.  Ask me how I know.

2.  If you use woven plaids, like those in the two quilts I showed you, there's no obvious right or wrong side of the fabric.  So it's very easy to lose track of which side should be up.  That results in a block where the seam slopes up instead of down, or if you're really not paying attention, a block where some of the seams face up and others face down.  Ask me how I know.  I suggest you put a pin in the right side, or use any other method that helps you keep track of which way is up.

3.  If you want to make the up-and-down mountain effect of the three quilts I showed you last week, you will need to make half of the blocks slope up and the other half slope down.  I strongly suggest you make all the ups first and get them on the design wall.  Then make all of the downs.  Make sure you use some of the same fabrics in each set, otherwise it will probably look weird to have all the up blocks predominantly blue or the brightest fabric show up only in the down blocks.  If this sounds too complicated, then forget about the mountain effect and just have all your blocks slope in the same direction.  The quilt will look just as nice.

Important:  Each time you make a new cut, the seam eats up a half inch of height.  So if you're planning to make blocks with just two rails (one seam), add a half inch to the blocks you cut in the first place.  If you want seven-inch blocks, cut 7 inches wide and 7 1/2 inches tall.  Or better yet, cut 7 1/4 inches wide and 7 3/4 inches tall just to give yourself some wiggle room in case the seams run a little bit wide.  You can cut the block down to size after it's all sewed and pressed.

Cutting dimensions
- always add 1/4 inch width to trimmed block dimension
- always add 1/4 inch height PLUS:
   - for one seam (two rails) -- add 1/2 inch height
   - for two seams (three rails) -- add 1 inch height
   - for three seams (four rails) -- add 1 1/2 inch height
   - for four seams (five rails) -- add 2 inches height

Happy sewing!  Let me know how it works out for you.