Bobbin thread showing on top of embroidery? How to fix it

Bobbin thread shows on top when the upper thread is pulling harder than the bobbin thread. Brother names two causes: upper thread tension that’s too tight and a bobbin installed incorrectly. Rethread, reseat the bobbin so its thread passes under the tension spring, then loosen the upper tension one step at a time and check a satin test stitch. You finish a red satin monogram and see little white specks along the edges of every letter. That white is bobbin thread being pulled up to the front. It’s a balance problem between the top thread and the bobbin thread, and it’s usually quick to fix once you know which side is out of balance.

This guide uses Brother’s manual and Madeira’s tension guidance to show what causes it, how to test it and how to fix it without making things worse.

Why does bobbin thread show on top?

Every stitch is a tug-of-war. The top thread comes down through the fabric, the bobbin thread comes up, and they should lock together just under the fabric surface, on the back. If the top thread pulls harder than the bobbin, it drags the bobbin thread up to the front.

Brother’s List of Symptoms gives two causes when bobbin thread is visible on the top of the fabric:

1. Upper thread tension is too tight.
2. The bobbin is installed incorrectly.

Brother also lists bobbin thread that was wound incorrectly as a related cause.

Quick diagnostic table

How do you check thread tension?

Brother’s description

Brother’s tension page describes the correct result as upper thread appearing slightly on the wrong side of the fabric. If bobbin thread appears slightly on the right side, the upper tension is too tight and Brother says to loosen it. If loops appear on the right side, the upper tension is too loose and you should tighten it.

Madeira’s 1/3–2/3 satin test

Madeira suggests stitching a simple satin stitch as the best way to see whether tension is right. Turn the fabric over: correct tension for satin stitches should show about 1/3 bobbin thread and 2/3 top thread color on the underside. In practice that’s a band of bobbin color down the middle with top thread color on both sides.

Use a contrasting top color for the test so it’s easy to read. Stitch on the same fabric and stabilizer you’ll use for the real piece.

A caveat on Madeira’s numbers. The same Madeira page lists tension values in grams for bobbin and top threads, measured with Towa and Tajima tension gauges. Those are tools for commercial machines. Brother’s embroidery machine manual has you set upper tension with plus and minus buttons and a tension number on the screen, so use the visual 1/3–2/3 test, not the gram figures.

How to fix bobbin thread showing on top

Step 1: Rethread the upper thread

Tension problems and threading problems look alike. Cut the thread at the spool, pull it out through the needle, raise the presser foot and rethread. Brother’s threading instructions say the machine can’t be threaded if the presser foot isn’t raised. A thread that has slipped out of a guide or is catching on the spool can add drag and pull the bobbin thread up.

Step 2: Reseat the bobbin

Remove the bobbin and reinstall it the way your manual shows. Brother’s instructions for its embroidery machines say to set the bobbin so the thread unwinds to the left, guide the thread through the slit in the needle plate and pull it lightly so it enters the bobbin case’s tension spring. That spring is what gives the bobbin thread its tension. If the thread misses it, bobbin tension is close to zero and the top thread wins every time.

Brother also warns to use a correctly wound bobbin, or the tension may be incorrect. While the bobbin is out, brush lint from the case. Madeira suggests cleaning the bobbin case with compressed air when you change bobbins.

Step 3: Loosen the upper tension

If the bobbin was seated correctly, the upper tension is the next suspect. On Brother machines, you touch the minus button on the screen to loosen it. Go one step at a time and stitch the satin test after each change.

Don’t loosen it all the way. Brother notes that if upper tension is set extremely loose, the machine may stop during embroidering.

Step 4: Check the bobbin thread

Brother says to use the included or a recommended embroidery bobbin thread, and that its included bobbin case is set for 90 weight bobbin thread. Brother’s PWB350 prewound bobbins are listed as 90 weight, designed for Brother embroidery-only machines.

Not every maker uses the same weight. Sulky’s thread guide lists its bobbin thread as 60 weight spun polyester, which is heavier than 90 weight. Brother says that if you use a different weight of bobbin thread, the bobbin case tension screw can be adjusted if necessary. So if the problem started when you changed bobbin thread, go back to the recommended thread first.

Prewound bobbins must also match your machine’s bobbin size. Madeira notes that prewound bobbins give consistent tension. Our embroidery thread guide covers bobbin thread choices.

Step 5: Adjust the bobbin case only as a last step

Some Brother machines come with a bobbin case that has no color on its screw, and Brother’s manual explains how to adjust it. For bobbin thread that’s too loose, Brother says to turn the slotted (−) screw clockwise about 30–45 degrees. For bobbin thread that’s too tight, turn it counterclockwise about 30–45 degrees. Remove the bobbin first.

Brother’s cautions are important:

• Don’t adjust the Phillips (+) screw on the bobbin case.
• Don’t use force if the slotted screw is hard to turn.
• Turning the screw too much may damage the bobbin case.

Madeira recommends setting bobbin tension correctly before managing top tension, which is the commercial approach. On a home machine, it’s safer to change upper tension first, because you can always return it to the default number. If you do adjust the case, turn it a small amount, retest, and note how far you turned it.

Step 6: Rule out the design

If bobbin thread shows on only one design, look at the file. Very narrow or very dense satin columns are harder to balance. Run a test with a different design. If the other design is fine, the problem is the digitizing, not your machine. See embroidery design resizing if you’ve shrunk the design.

How do you prevent it?

• Rethread and reseat the bobbin every time you change bobbins or spools.
• Stick with one bobbin thread that matches what your machine is set for.
• Stitch a tension test when you change thread type, such as moving from polyester to metallic.
• Keep the bobbin area free of lint.
• Write down your settings. If a fabric or thread combination needs a different upper tension, note it so you can repeat it.

When top tension is too tight, it often causes other problems too. If your thread is also snapping, see why embroidery thread keeps breaking. Tight tension can also draw fabric in, which we cover in embroidery puckering. If you’re seeing tangles underneath instead, go to embroidery machine bird nesting.

New to all of this? Our how to use an embroidery machine guide covers threading and a first stitch-out, the glossary explains the terms, and more fixes are in our troubleshooting guides.

What to buy

The supplies this guide calls for, with what to check before buying. Prices change often — confirm with the seller.

• Embroidery bobbin thread or prewound bobbins — Lighter bobbin thread keeps the back of the design flat and reduces bulk.
• 40 wt polyester embroidery thread set — A starter range of colors in the weight most home designs are digitized for.
• Embroidery needles (75/11) — Embroidery needles have a larger eye and groove that protect rayon and polyester thread at speed.
• Tweezers — Pull out trimmed tails, lint and stray threads around the needle plate.