What this site covers

Threading, tension, cleaning and oiling guides for home sewing machines and sergers.

Stitch Manual

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Guides for Singer, Brother, Janome and Juki machines and sergers

Setting top and bobbin tension

Rethread before you touch the dial, and on most modern machines never touch the bobbin screw at all.

Read the stitch first

A balanced lockstitch locks the two threads in the middle of the fabric, so neither shows on the wrong side. When it is off, the stitch tells you which way. Top thread lying flat with bobbin thread pulled up to the surface: the top is too tight, or the bobbin is too loose. Loops of top thread on the underside: the top is too loose, or more often misthreaded. Sew two layers of scrap in contrasting colors top and bottom so you can see it.

Fix it in this order

  1. Rethread the top with the presser foot raised, and reinsert the bobbin the right way round. Brother's CS7000X manual says to return the dial to 4 and rethread before correcting anything else.
    Presser foot lever raised
  2. Check the needle and thread suit the fabric and each other. Use the same thread top and bottom while you test.
  3. Now move the top tension dial, one number at a time, and resew. On every machine here whose manual numbers the dial, higher numbers tighten.
    Tension dial set at 44
  4. Only if the top dial cannot balance it, and only on a machine whose maker tells you to, adjust the bobbin case screw a small amount.
    Removable bobbin case with the thread drawn under the tension spring

Starting points from the manuals

What you seeCheck, in this order
Singer Heavy Duty 4423Basic setting 4; 90 percent of sewing between 3 and 5. Bobbin tension factory set, do not adjust.
Brother CS7000XReset to 4. No owner bobbin adjustment.
Brother XM2701, LX3817No standard number printed. No owner bobbin adjustment.
Brother 1034D sergerEach dial 0 to 9; 4 for most work. Adjust left needle, right needle, upper looper, lower looper in that order.
Janome HD3000Set the number at the mark; slightly weaker for zigzag. For lighter bobbin tension Janome offers the low-tension holder 202006008.
Juki TL-2010QSet the bobbin first: the case slides down slowly when shaken by its thread. Then match the top dial.
Featherweight 221Dial 0 to 9. Reset: No. 50 thread, top at 3, adjust the bobbin screw until the stitch locks in the middle.
Singer 15-91Dial 0 to 9. Reset: size 50 thread, top at 4, adjust the bobbin until it locks in the middle.
Singer 401ALower number if too tight, higher if too loose. Bobbin case screw clockwise to tighten, counterclockwise to loosen.

Hold off on the bobbin screw on modern drop-in machines. Singer says the 4423's bobbin tension needs no adjusting, and Brother gives owners no bobbin adjustment for the XM2701, LX3817 or CS7000X. On those, a bobbin-side fault is a threading fault: the thread missed the spring in the case.

Tension on your machine

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