What Changes in a Leather Goods Pattern

What you take from this lesson: Be able to read and use a bag or backpack pattern without carrying over the assumptions of clothing.

There is no size range

This is the most obvious difference and the one that simplifies everything the most. A bag has a single size: there is no grading, no deciding how many units of each size to produce, and no dead stock sitting around because you had leftover 3XL.

What the pattern does give you are the finished measurements of the completed piece: height, width and depth. That lets you decide, before cutting, whether the size works for what you want to sell.

Seam allowances are larger

In leather goods, seams have to carry weight and take pulling, not just the movement of a body. Seam allowances are more generous than in clothing, and seams are often reinforced or topstitched twice.

Also, many leather goods materials do not fray (faux leather, eco-leather), so you do not need to finish the edge, but you do need to hold the seam: the typical failure point of a bag is not the fabric, it is the handle attachment.

There are almost always two patterns: outer and lining

A well-made bag has a lining. And the lining does not use the same pattern as the outer: it is usually a few millimeters smaller, because it sits inside and has to fit without wrinkling.

That means a leather goods pattern, in practice, comes with two sets of pieces: those for the outer material and those for the lining, plus the interfacing pieces if it uses interfacing.

Volume is built with pieces, not curves

In clothing, volume comes from curves and darts that follow the shape of the body. In leather goods, volume is built with straight pieces: a base, two sides, a front and a back.

That is why bag patterns look deceptively simple: rectangles and trapezoids. The hard part is not drawing each piece but making sure the lengths of the edges that are joined match exactly, because here an error of half a centimeter cannot be hidden by stretching the fabric.

Common mistakes

• Using the same pattern for the outer and the lining: the lining ends up wrinkled or pulls on the outer.
• Applying clothing seam allowances to a seam that will carry weight.
• Assuming the material will "give" like fabric: faux leather does not give.

In short

No size range, larger seam allowances, a separate pattern for the lining, and volume built with straight pieces instead of curves.