Skipped stitches

Why a machine skips

A stitch forms when the hook or looper point catches the loop of top thread that forms behind the needle as it starts to rise. Anything that spoils that loop, or moves it away from the point, makes the machine miss. Every manual we draw on puts the same culprit first: the needle. Bent, blunt, the wrong size for the thread, the wrong type for the fabric, or simply not pushed all the way up into the clamp.

Work through these in order

1. Unplug or switch off, and fit a brand new needle of the right system and size. Do not trust a needle that looks fine.
2. Put it in the right way round and push it fully up before tightening. Flat side to the back on most modern machines; to the left on the Featherweight and 15-91; to the right on the Juki TL-2010Q.
3. Match the needle to the fabric. Knits and stretch fabrics want a ball point or blue tip needle; Janome says the blue tip prevents skipped stitches on fine and stretch fabric.
4. Rethread the top with the presser foot up.
5. Take off the needle plate and brush out the lint around the feed dogs and hook. Brother lists dust under the needle plate as a cause.
6. Check the presser foot is attached properly and its pressure is not too light. Janome and the Brother 1034D serger both list low foot pressure.

If it still skips

Only after all of that does timing come into it. On modern machines, timing is a service center job. On vintage Singers, the service manuals give owners a way to check it with the timing marks on the needle bar:

• Featherweight 221: hook point at the center of the needle when the lower mark is centered on the upstroke.
• Singer 401A: the same check, plus .018 inch between needle and position finger.
• Singer 15-91: shuttle timing is pinned at the factory and only moves after damage or a replacement driver.

On your machine

• Brother XM2701, LX3817 and CS7000X: household needles, flat side back; clean the race under the needle plate.
• Brother 1034D serger: SCHMETZ 130/705H, inserted correctly, and threaded in order: upper looper, lower looper, right needle, left needle.
• Singer Heavy Duty 4423: Singer says to change the needle at the first skipped stitch.
• Janome HD3000: blue tip needle for stretch and synthetics; increase presser foot pressure.
• Juki TL-2010Q: flat face to the right, fully up.