Metallic thread: needle, speed, tension and delivery settings that stop breaks and shredding

Metallic thread has a reputation for breaking, shredding and looping, and most of it is earned only when the thread is run like ordinary polyester. Its construction is different, so the needle, the delivery, the speed and the design all need to change together. Set them up in the order below and most metallics stitch reliably.

Why metallic thread behaves differently

Most embroidery metallics are one of two kinds.

• Wrapped metallic. A core, often polyester or nylon, wrapped with a thin metallized foil. The foil gives the shine; the core gives the strength.
• Flat film or holographic thread. A narrow ribbon slit from metallized polyester film. It is very bright and very sensitive to twisting.

Both are stiffer and springier than polyester or rayon, and both have memory: they hold the curl of the spool. The foil cracks if it is bent sharply, rubbed or heated, and once it cracks it peels back and shreds. Every fix for metallic thread does one of three things: gives the thread a wider, smoother path, lets it come off the spool without twist, or slows the machine so friction and snatching drop. Embroidery thread types compares metallics with the other fibers.

Set up for metallic in this order

1. Fit a fresh needle with a larger, polished eye. A metallic needle has an elongated eye and a polished groove made for this thread; a topstitch needle, with an even larger eye, is a common alternative. Sizes 80/12 or 90/14 are typical starting points. A worn needle or a burr in the eye shreds metallic long before you would notice it with polyester. See embroidery needles.
2. Feed it without twist. Flat film thread should come off a vertical pin or stand so it unrolls flat. Wrapped metallics often run better from a stand, with a thread net if the spool lets coils slip off. See thread stands and delivery.
3. Slow down. Running at roughly 50 to 70 percent of the machine's top speed is a common starting point. Lower speed cuts friction and heat at the eye and gives the springy thread time to settle between stitches. Speed settings explains why.
4. Lower top tension slightly. Metallic thread meets more friction in the discs and the eye, so the same setting pulls harder than it does on polyester. Reduce in small steps, test, and stop as soon as the thread runs cleanly.
5. Leave the bobbin alone. Use your normal bobbin thread and bobbin tension. Changing the bobbin at the same time as the top makes it impossible to tell which change helped.

These are directions of change from your usual embroidery setup, not fixed values. Machines, needles and thread lines differ, so follow the thread maker's and machine maker's guidance where they give it.

Designs that suit metallic thread

The setup can only do so much if the design fights the thread. Metallic runs best in designs that give each stitch room.

• Lower density. A dense fill forces the needle through thread already packed in place, which grabs and abrades the foil. Designs digitized for metallic use more open fills, or you can reduce density in software if you have the object file. See stitch density.
• Longer stitches. Very short stitches bend the thread sharply many times in a small space. Running stitches and satins of moderate length show off the shine better anyway.
• Satin over fill where possible. A satin column lays long, parallel strands that catch the light; a dense tatami fill buries it.
• Little or no tiny lettering. Small letters combine short stitches, tight turns and density. Stitch them in polyester and save metallic for accents.
• Metallic last, or on top. Where the color order allows, stitching metallic over finished areas avoids running other colors through it.

What goes wrong, and what it means

Shredding: frayed foil above the needle

Eye too small or worn, speed too high, or twist from delivery. Change the needle first, then slow down. Thread shredding covers shredding in more depth.

Clean breaks

Usually a snatch: the thread caught on the spool, a guide or a burr. Check delivery and the thread path by hand. See thread breaking.

Loops and kinks on the surface

The springy thread is coming off unevenly and arriving as slack. Use a stand or net, and confirm the thread is seated in the tension discs. See loops on top.

Bobbin thread on top

Top tension lowered too far, or still too tight in a dense area. Run an I-test in the metallic and adjust the top in small steps.

Breaks only in one dense area

The design, not the setup. Reduce density there or stitch that area in a standard thread.

Some embroiderers use thread lubricant or silicone products on difficult threads. Machine makers differ on whether anything should be added to the thread path, so check your manual before you try one.

Planning time and testing

Slower speed lengthens run time, so allow for it when quoting or scheduling; the stitch time calculator lets you lower the speed to see the effect. Change one setting per test, starting with the needle, and keep notes on what worked for each thread line. The Stitch-Out Tuning Method gives a short test sequence for doing that on the same fabric and stabilizer as the real job.