How to lay out and cut fabric on grain

To cut on grain, fold the fabric with the selvedges together, then place each pattern piece so its grainline arrow is exactly parallel to the selvedge: measure from both ends of the arrow to the selvedge and shift the piece until the two distances match. Put place-on-fold edges right against the fold, weigh or pin everything down, and cut on the solid line with long, smooth strokes.

What is the grain of a fabric?

A woven fabric is made of two sets of threads. The lengthwise threads (the warp) run parallel to the selvedge, also spelled selvage, the finished edge that does not fray. They are the strongest and stretch the least, which is why the grainline of most pieces follows them. The crosswise threads (the weft) run from selvedge to selvedge and give a little more. The bias, at 45 degrees to both, stretches the most and drapes softly: slip dresses and binding strips are cut on it on purpose.

Knits have grain too. The ribs (columns of loops) run lengthwise, and the greatest stretch usually runs across, from selvedge to selvedge. Cut knit pieces with the grainline along the ribs so that stretch goes around the body.

Before you cut: prepare the fabric

1. Pre-wash and dry it the way you will wash the garment. See pre-washing fabric.
2. Press it flat, including the crease from the bolt if it will come out. A crease that will not press out should not land in the middle of a front.
3. Straighten the cut ends. On cotton and linen, snip into the selvedge and tear across, or pull a crosswise thread and cut along the line it leaves. On other fabrics, use a large set square against the selvedge.
4. Find the right side. Prints are brighter and sharper on the right side. On plain fabrics, compare both sides in daylight, or pick one and mark the wrong side of every piece with chalk.
5. Clear a big, flat surface. A table, a large cutting mat or a clean floor. Fabric hanging over the edge pulls the layers off grain.

How to fold fabric for cutting

• Lengthwise fold (the usual one). Selvedge on selvedge, right sides together, fold along the length. Every piece cut through both layers comes out as a mirrored pair, and place-on-fold pieces go against the fold.
• Partial fold. When the pieces are narrow, fold one selvedge in only as far as the widest fold piece needs, and use the remaining single layer for other pieces. Check that the fold is the same distance from the selvedge all along.
• Crosswise fold. Fold one cut end over to the other, across the width. Useful for wide pieces, but on fabrics with a nap or a one-way print the top layer ends up upside down: cut those single layer instead.
• Single layer. For slippery fabrics (viscose, silk, satin), very large pieces such as circle skirts, and anything you need to match exactly. Cut one piece, then turn the paper over to cut its mirror.

How to place pattern pieces on grain

1. Find the cutting layout. Sewly patterns include cutting layouts for 110, 140 and 150 cm (45, 55 and 60 in) wide fabric; commercial patterns print them on the instruction sheet. Find the one for your width and size, and circle it.
2. Place the biggest pieces first, starting with those on the fold, then fit the smaller ones in between.
3. Push fold edges against the fold. No gap at all: every millimeter of gap doubles in the cut piece.
4. Measure the grainline. With a ruler or tape, measure from the top of the arrow to the selvedge, then from the bottom. Pivot the piece until both numbers match, then pin or weigh that end first.
5. Secure the piece. Pattern weights (tins, large washers, smooth stones) are fast and do not distort the fabric. If you pin, place pins inside the cutting line, at right angles to the edge, about every 15 cm (6 in).
6. Check the cut counts. "Cut 2 (a pair)" through two layers gives one left and one right. "Cut 4 (pairs)" means placing the piece twice on the folded fabric.
7. Draw the rectangles. Waistbands, ties and ruffle panels that the pattern gives as cutting dimensions are drawn straight on the fabric with a long ruler and chalk, along the grain the pattern states.

Nap, one-way prints, stripes and checks

Velvet, corduroy, faux fur, brushed fabrics and many satins look different depending on the direction of the light on their surface: this is the nap. Prints with a top and a bottom (trees, animals, lettering) behave the same way. For both, every piece must point in the same direction. This "with nap" layout often needs more fabric; the fabric yardage calculator helps you check before you buy.

For stripes and checks, fold so the stripes on the top layer sit exactly on the stripes below, pinning through both layers every 10 cm (4 in), and place notches that will meet on the same stripe on both pieces. Cutting single layer is often easier and more accurate.

How to cut cleanly

• Shears: use long, full strokes with the lower blade resting on the table. Do not lift the fabric to cut.
• Rotary cutter: on a self-healing mat, roll away from you, against a ruler on straight edges. A 28 mm cutter handles tight curves; a 45 mm one suits most garment work.
• Move around the table instead of turning the fabric, especially once it is pinned.
• Notches: cut them outward as small triangles, or cut straight past them and snip 3 mm (1/8 in) into the allowance afterwards.
• Leave the paper on until you have transferred the markings.

Common mistakes and fixes

• Pieces cut off grain. The garment twists or hangs unevenly. Recut if you have enough fabric; on a skirt you can sometimes shift a side seam slightly, but it is a compromise.
• Two left sleeves. A pair was cut from a single layer without turning the paper over. Cut a new sleeve with the paper face down.
• Fabric shifted while cutting. Slippery fabric moved on the table. Lay tissue paper or an old cotton sheet underneath and cut through both, or use more weights and a rotary cutter.
• Not enough fabric. Before giving up, try a partial fold, place pieces head to tail (on fabrics without a nap), or cut facings and pocket bags from a contrast fabric.
• Fabric hanging off the table. Its weight stretches it off grain. Fold the excess up and keep it on the table while you cut.
• Cutting with blunt shears. Chewed edges and layers that slide apart. Keep a pair of shears for fabric only, and have them sharpened when they start to fold the fabric instead of cutting it.

When everything is cut, keep each piece with its paper until the markings are on the fabric. That small habit saves a lot of guessing at the machine.