Guide - How to machine sew leather?

Before embarking on leather sewing projects, we invite you to carry out tests beforehand to assess the power of your machine.

Unlike sewing fabric, there are no seam allowances to add on patterns. Don't rush when sewing leather by machine: once the leather is stitched, small holes are visible when unpicking!

WHAT IS THE DIFFERENCE BETWEEN HAND STITCHING LEATHER AND MACHINE STITCHING?

SADDLE STITCH (HAND SEWING):
The saddle stitch works by passing each of the two threads above and below the thicknesses of the leather. If one of the threads breaks, the stitching does not come undone and can easily be repaired (e.g. second line).

MACHINE SEWING:
As for machine sewing, the threads never cross both layers of leather. The seam is therefore more fragile and easily and completely undoes if one of the threads breaks (e.g. second line)

Saddle stitching is therefore more aesthetic and solid than machine stitching but requires much more time and patience. Machine stitching is ideal for assemblies that will not be subjected to high tension.

WHAT IS THE QUICK SEWING AWL?

The automatic awl , also called a quick-sew, is a tool designed for people who are new to leatherwork: it allows you to quickly sew leather using an automatic system. Be careful, it does not allow you to make a saddle stitch but a "machine" stitch. We do not recommend it if you want to have a solid and "traditional" leather seam.

HOW TO SEW LEATHER WITH A SEWING MACHINE?

Do you have a household sewing machine and want to start sewing leather? Here are some essential points to know before you start:

• The sewing machine: the ideal for sewing leather is to have a powerful machine with a triple feed (in order to feed the leather more easily when sewing) otherwise you can add a double feed foot to your family machine. We do not recommend sewing leather with a first price family machine (e.g. Silvercrest).
  
  Unfortunately, we cannot recommend a particular machine, everything will depend on the use (private or professional). We are fans of the Toyota Power Fabric (we use it for all our tutorials) but it is unfortunately no longer for sale (perhaps on second-hand sites). Singer has released a special industrial leather sewing machine - reference 9900 (we have a partnership with them - see the article sheet below) . Many machines are compatible with sewing leather but you must inquire directly with the sellers: PFAFF Ambition 610/620 - PFAFF Passport 3.0 - Veritas Power Stitch (for example) .

• The choice of leather: if you do not have a professional machine special for sewing leather you cannot choose a leather that is too thick (at the risk of damaging the grain of the leather and your machine).
  We therefore advise you to select thin and supple leathers (0.8 to 1 mm - maximum 1.2 mm thick) – for example leathers from the Sweet 2, Granite or even Satinlys range.

• To know the maximum thickness that your machine can support, we invite you to do some tests beforehand. The thicker the leather, the more powerful the motor of your sewing machine will need to be. Don't forget to adjust the tension of your machine correctly.

• Stitch length: Set your machine to a long stitch (but not too long) to prevent the leather from tearing: a stitch length of 3 to 3.5 mm (short stitches are so close that they will tear the leather with use) .

• The spool of thread: choose polyester thread with a diameter of 0.35 to 0.50 mm (No. 40, No. 30 or No. 20) for leather goods and small leather goods.

• Clip clamps: they are ideal for assembling and holding your leather pieces during machine sewing or gluing. Very practical, they avoid piercing the leather with pins. Alternatives: double-sided adhesive tape or water-based glue.
  
  Tip for the adhesive tape : make sure that it is positioned in the seam allowance and not on the seam line (otherwise your needle may not appreciate it => it will "get clogged").

• Teflon/non-stick presser foot: to more easily feed your piece of leather and obtain regular stitches (on sale on our site).

• Which needle to use to sew leather by machine? We recommend using special leather machine needles. These needles are made of hardened steel and are therefore very strong (the risk of breakage is lower). Needle with a sharp point for stitching leather. Size (NM) 90 to 120.

HOW TO READ A NEEDLE PLATE?

Needle size is often referred to as NM or SIZE which both represent the diameter of the needle shank (SIZE is the diameter of the needle shank in the Singer and American system).

Metric Number (NM) equals needle shank diameter x 100

In the example below, the needles have a NM 110 and SIZE 18. The needle diameter is therefore 1.1 mm (110/100 = 1.1).

WHICH NEEDLE SHOULD I CHOOSE ACCORDING TO THE DIAMETER OF THE THREAD?

Here is a table (given for information purposes) to guide you.

Wire diameter	NM Needle
Polyester thread no. 40 – Diameter 0.35 mm	90 - 100
Polyester thread no. 30 – Diameter 0.41 mm	100 - 110
Polyester thread no. 20 – Diameter 0.50 mm	110 - 130

Thread No. 40 is generally used for small leather goods creations or with fine leathers (e.g. clothing). Thread No. 30 for leather goods creations and thread No. 20 for saddlery.

IN ADDITION TO OUR ARTICLE:

We invite you to consult the article by blogger Jane Emilie "What material do you need to sew bags?".

VIEW BLOG POST >

LEATHER TUTORIALS
WITH A MACHINE SEWING