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How to check and set embroidery machine tension

Published

5/8 in seam allowance

Short answer

Stitch a satin column or a capital I and look at the back. Balanced embroidery tension shows a center stripe of bobbin thread about one third of the column width, with top thread on each side. Too much bobbin showing means the top tension is too tight; no bobbin showing means it is too loose. Adjust top tension in small steps and retest.

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Embroidery tension works differently from sewing tension. In a good embroidery stitch, the top thread is pulled slightly to the back so it wraps the edges of the design and no bobbin thread shows on the front. The standard way to check this is the I-test, which reads the back of a satin column. This guide explains the test, what each result means, the order to check things before touching the dial, and how to adjust on machines with a tension dial or a tension setting on the screen. Brother, Janome, Singer and other machines handle this a little differently, so check your manual for where the setting lives.

What balanced embroidery tension looks like

On the front of the design, you should see only top thread, with smooth satin stitches and no bobbin thread peeking through. On the back of a satin column, you should see a stripe of bobbin thread in the center about one third of the width, with top thread on each side of it.

This is different from a normal sewing lockstitch, where the threads lock in the middle of the fabric. In embroidery, the lock is pulled slightly to the back so the top thread covers the edges cleanly.

Cross-section of a lockstitch in two layers of fabric, balanced and with too much top or bobbin tensionNeedle (top) threadBobbin threadBalancedThreads lock between the layersTop too tightBobbin thread shows on topBobbin too tightNeedle thread shows underneathBlack dots mark where the two threads lock. Rethread and change the needle before turning the tension dial.
A home sewing machine makes a lockstitch: the needle thread and the bobbin thread interlock once per stitch.

How to do the I-test

Repeat the test any time you change thread type, bobbin thread or fabric weight significantly, since each can shift the balance.

  1. 1

    Hoop medium-weight woven fabric with a medium tear-away stabilizer.

  2. 2

    Use a new 75/11 embroidery needle, 40 wt embroidery thread on top and the bobbin thread your machine recommends.

  3. 3

    Stitch a satin column at least 1/4 inch wide, or a capital I in a block font. Many embroiderers use a contrasting top thread color to see it clearly.

  4. 4

    Remove the hoop and turn the fabric over.

  5. 5

    Look at the satin column on the back and estimate how much of its width is bobbin thread.

Reading the result

  • Bobbin about one third, top thread on both sides

    What it means
    Balanced
    What to do
    No change needed

  • Bobbin wider than one half

    What it means
    Top tension too tight (or bobbin too loose)
    What to do
    Loosen top tension slightly and retest

  • Little or no bobbin visible, mostly top thread

    What it means
    Top tension too loose
    What to do
    Tighten top tension slightly and retest

  • Bobbin thread showing on the front

    What it means
    Top too tight or bobbin issue
    What to do
    Rethread, check bobbin, then loosen top tension

  • Loops of top thread on the front or back

    What it means
    Threading error or very loose top tension
    What to do
    Rethread with the presser foot up first

Check these before you adjust tension

Most apparent tension problems are actually threading, bobbin or needle problems. Changing the tension dial to compensate for a threading mistake makes things worse once the mistake is fixed.

  • Rethread the top thread with the presser foot raised so it seats in the tension discs.
  • Check the spool cap and that thread unwinds smoothly without catching.
  • Use the bobbin thread type recommended for your machine and confirm the bobbin is inserted the right direction.
  • Clean lint from the bobbin case and hook area.
  • Install a fresh embroidery needle of the right size.
  • Make sure the thread is not old, brittle or a much heavier weight than the design expects; see machine embroidery thread weights.

Note.Avoid adjusting the bobbin case screw unless your manual describes it. Bobbin tension is set at the factory, and small turns make big changes.

How to adjust embroidery tension

On machines with a tension dial, turn it in small steps, then retest. Higher numbers usually mean tighter top tension. On many computerized embroidery machines, including many Brother models, embroidery tension is set in a settings screen or in the embroidery screen rather than with a dial. The location and scale vary by model, so look up embroidery tension in your manual.

Change one thing at a time and retest with the I-test after each change. Note the setting that works for each thread type you use. Some embroiderers keep a separate bobbin case marked for embroidery when the machine maker offers one, which avoids readjusting a shared case. For Brother-specific symptoms, see Brother embroidery machine problems.

  • Metallic or specialty thread

    Typical adjustment
    Often a slightly looser top tension; use a metallic needle

  • Thick 30 wt thread

    Typical adjustment
    Larger needle, test tension

  • Dense satin columns pulling fabric

    Typical adjustment
    Check stabilizer first, then ease top tension slightly

  • Bobbin peeking on top at edges

    Typical adjustment
    Ease top tension, check bobbin thread and needle

Tension and puckering

Tight top tension can pull fabric in and add to puckering, but stabilizer and hooping are much more common causes. If designs pucker, work through the machine embroidery puckering guide before changing tension. Thread breaks and shredding are also more often needle or threading problems; see embroidery thread shredding and breaking. The needle and thread finder suggests needle sizes for each thread type.

If tension seems impossible to balance after all the checks, the tension discs or bobbin case may need service. Our guides to the best embroidery machines for beginners and best Brother embroidery machines cover models that make tension setup straightforward.

See beginner embroidery machines →

Frequently asked questions

What should embroidery tension be set at? There is no single number. Settings vary by machine, thread and fabric. Use the I-test and aim for about one third bobbin thread on the back of a satin column.

Why is bobbin thread showing on top of my embroidery? Usually the top tension is too tight relative to the bobbin, or the bobbin is inserted wrong or uses the wrong thread. Rethread and check the bobbin first.

Is embroidery tension the same as sewing tension? No. Embroidery tension pulls the top thread slightly to the back, while sewing tension locks threads in the middle of the fabric.

Should I change the bobbin tension? Rarely. Adjust the top tension first and leave the bobbin case alone unless your manual describes how to adjust it.

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