Manufacturer · Fashion & Home Accessories
A leather needle differs from a fabric needle in its point. In machine sewing it has a cutting point that makes a small slit in the leather, instead of pushing the fibres apart like a textile needle. In hand sewing, blunt needles are used that pass through pre-punched holes. The needle size is chosen according to the thickness of the thread, and the shape of the point according to the leather and the desired look of the seam.
Why a special leather needle is needed
Woven fabric consists of yarns between which the needle can pass by pushing them apart. Leather is a dense material without such gaps. An ordinary round-point needle has to pierce and stretch the leather, which requires great force, heats the needle and often leads to skipped stitches and broken thread. A cutting point opens a path for the thread with minimal effort and gives a clean, uniform hole.
Leather needle: types of cutting points for machines
Needle manufacturers use different letter designations, but the principle is the same – the point is ground like a small blade with a specific shape and orientation relative to the direction of the seam. The orientation determines how the stitch lies.
| Point shape | How it cuts | Seam appearance, use |
|---|---|---|
| Angled cutting point (e.g. LR) | At an angle of about 45° to the seam | Stitches lie slightly slanted, a decorative look; the most common for footwear and leather goods |
| Mirror angled point (e.g. LL) | At an angle in the opposite direction | Slant in the opposite direction, used for symmetry |
| Cross cutting point | Perpendicular to the seam | Straight stitches, allows a denser stitch length |
| Lengthwise cutting point | In the direction of the seam | Stitches sink in, suitable for long stitches and thick threads |
| Triangular point (e.g. DI) | With three cutting edges | For hard and thick leather, many layers |
| Diamond point (e.g. D) | With four edges | For hard materials, cutting effect in two directions |
| Round point | Does not cut, pushes apart | Faux leather, textiles, coated materials |
Synthetic leather and coated materials are not sewn with a cutting point. They do not have a fibrous structure like genuine leather, and the slit can continue to tear under tension. For them a round or slightly rounded point is used.
Needle size relative to the thread
The needle size (Nm) corresponds to the diameter of the blade in hundredths of a millimetre – an Nm 110 needle has a diameter of about 1.1 mm. The thread must pass freely through the eye and lie in the groove of the needle. If the needle is too small, the thread rubs, heats up and breaks. If it is too large, the holes are too wide and the seam looks coarse.
| Thread | Needle Nm (guide) |
|---|---|
| Tex 30 | 80–100 |
| Tex 45 | 100–110 |
| Tex 70 | 110–130 |
| Tex 90 | 130–140 |
| Tex 135 | 140–160 |
| Tex 210 | 180–200 |
The values are approximate. Check the thread manufacturer's recommendation and sew a test seam.
Needle system
Besides the point and the size, the needle must suit the machine. The system determines the length, the shape of the shank and the position of the eye. Industrial flatbed machines and the post-bed machines used in footwear production use different systems. Fitting a needle of the wrong system, even with the correct size, leads to skipped stitches or striking the hook. Information on the system is in the machine manual or on the old packaging.
Hand needles for leather
Blunt needles
When hand sewing with a punch or awl, the holes are already made. The needle only has to carry the thread through, without cutting the leather and without piercing the thread already in the hole. That is why blunt needles with a rounded point and a large eye for waxed thread are used. This is essential for the saddle stitch, in which both needles pass through the same hole.
Triangular (glover's) needles
They have a small triangular cutting point and cut through thin leather without pre-punching. They are used for gloves, thin garment leather and repairs. They are not suitable for thick leather – they are hard to pull through, and the uneven holes give an uneven seam.
Curved needles
They are used in upholstery, repairs and sewing in places where you cannot reach the other side.
Signs of the wrong needle
- skipped stitches – often a round-point needle in leather or the wrong system;
- frayed and broken thread – size too small or a blunt point;
- large, torn holes – size too large or a cutting point in synthetic material;
- stitches with different slants – changing to a needle with a different point type in the middle of an order;
- overheating and marks on the leather – high speed with a thin needle and thick thread.
How often to change the needle
A cutting point dulls faster than a round point, especially with thick and hard leather. In production, the needle is changed regularly, not only when it breaks – a blunt needle increases the piercing force and damages both the leather and the thread. Also change it whenever you notice the seam getting worse. If you work with different types of leather, keep separate needles for each.
Leather threads matched to the needle
The needle and the thread are chosen together. The bonded leather threads in the threads for footwear and leather category are offered in thicknesses that correspond to standard needle sizes. For the textile parts of the product, such as linings, see sewing threads.
Advice from Polkom
Polkom is a manufacturer of accessories for fashion, furniture, footwear and bags, with over 30 years of experience. If you are not sure which combination of thread and needle to use, send us the type of leather, the product and the machine model via the contact page. We will advise you and send thread samples for a test seam.
