To assemble a tiled PDF sewing pattern, check the test square, lay the pages out in order using the page map, trim or fold away the blank margin on two edges of each page, then match the alignment marks and the pattern lines and tape the pages together one row at a time. Join the rows, check that every line runs on without a step, and cut out your pieces. The first time, a pattern of 20 to 30 pages takes most people 30 to 60 minutes.

What you need

  • Paper scissors, or a craft knife and a cutting mat (never your fabric shears)
  • Matte tape, the kind you can write on, or a glue stick
  • A ruler and a pencil
  • A large hard surface: a table, or a clean floor
  • A small weight or two, such as a mug, to hold pages while you align them

How tiled pages fit together

A tiled pattern is one large drawing cut into page-sized tiles, a method called pattern tiling. Each page has a blank margin around the drawing, because home printers cannot print to the edge of the sheet. When you remove the margin on one side of a page and lay that edge over the next page, the drawing continues exactly.

Most patterns label pages by row and column. On Sewly patterns, rows are letters and columns are numbers: A1 is the top left page, A2 is to its right, and B1 is below A1. The cover shows a page map of the whole grid. Pages that would be empty are not printed, so the grid can have holes: leave a gap there. Large plain rectangles such as waistbands and ties are not printed at all; you draw them on the fabric from their cutting dimensions.

Step-by-step assembly

  1. Check the scale. Measure the test square before anything else. If it is wrong, reprint following how to print a PDF sewing pattern: no amount of careful taping fixes a wrong scale.
  2. Lay out the pages. Put them on the table or floor in the order of the page map, row A at the top, without trimming yet. Check that none are missing.
  3. Trim two margins. On every page, cut away the margin along the left edge and the top edge, cutting along the edge of the printed area as the alignment marks show. Leave the right and bottom margins: they will sit under the neighboring pages. Pages in the first column do not strictly need the left edge trimmed, nor pages in row A the top edge, but trimming them does no harm.
  4. Join the first row. Lay A2 over the right margin of A1, so that the trimmed edge of A2 meets the end of A1's drawing. Match the alignment marks and every pattern line that crosses the join, then tape along the join. Add A3 the same way, and so on to the end of the row.
  5. Assemble the other rows. Build row B, row C and the rest in the same way, each on its own.
  6. Join the rows together. Lay row B over the bottom margin of row A, with its trimmed top edge on the end of row A's drawing. Match the marks along the whole length, then tape. Work from the middle outward so that small errors do not pile up at one end.
  7. Check the lines. Run your eye along each cutting line across the joins. A step of more than 1–2 mm (1/16 in) means a page has slipped; lift the tape and realign it.
  8. Cut out the pieces. Cut on the solid cutting line of each piece, keep every notch visible, and check the label for how many of each to cut. If you want to keep the printed pattern intact, trace the pieces instead of cutting them out.
Tip: Instead of trimming, you can fold the margin under along the same line. Folding is quicker; trimming is more accurate on patterns with many pages.

Tape or glue?

Tape is quick, holds well and lets you lift and adjust a page. Use matte tape so you can write on it, and do tape across lines you will cut through, because the tape helps the paper survive the scissors. A glue stick gives a flatter result for patterns you will trace or keep, but you cannot adjust once it dries, and too much glue wrinkles the paper. Many sewists tape while aligning, then add a little glue where pages overlap widely.

Keep errors from adding up

  • Assemble on a hard, flat surface; carpet lets pages shift.
  • Join pages row by row instead of building out in every direction.
  • Line up the pattern lines as well as the marks: if the two disagree, trust the lines.
  • Butt the edges exactly. A gap of 1 mm (1/32 in) at each of six joins adds 6 mm (1/4 in) across a large piece.
  • Keep the room still: a fan or an open window can lift a page you have not taped yet.
  • Tape each join first with short pieces across the line, check the next join, then run a long strip along the whole seam once the row is right.

Store or reuse your pattern

Write the pattern name, your size or measurements and the date on each piece. Fold pieces loosely along the original page lines or roll them, and keep them together in a large envelope or a hanging bag. If you will make the garment many times, trace the pieces onto sturdier pattern paper with all their markings, and keep the taped original as a reference.

Common assembly mistakes

  • Trimming into the drawing. Cut along the edge of the printed area, not inside it, or each piece loses a strip of width at every join.
  • Pages out of order. Check each page's label against the page map before taping.
  • Ignoring a wrong test square. Every piece will be off by the same percentage; reprint first.
  • Gaps between pages. Lines jump at the joins and pieces lose or gain width; lay edges exactly against each other.
  • Losing notches. On patterns that draw notches as small triangles outside the cutting line, cutting straight past them removes them. Cut around them.
  • Assembling pages you do not need. If you are leaving out a piece, check the page map and skip the pages that hold only that piece.

When the pieces are ready, move on to laying out and cutting fabric on grain. If taping dozens of pages is not for you, printing at a copy shop gives you large sheets instead.