make bikinis & sew on 4 way stretch spandex/lycra. I'm having an issue with stitches skipping.?

I use a zigzag stitch and every 7to10 stitches, my needle jumps & I get one straight stitch. How can I get a consistent run of stitches?
I have a new Singer Confidence 7470 sewing machine. Thank you!

Try a Schmetz "Stretch" needle of the appropriate size. They're designed to help stop skipping on fabrics with a lot of lycra. Also, consider using stabilizer on top of and/or underneath the fabric. Much of your skipping of stitches is probably caused by what's called "flagging", where the fabric hops up and down a bit with the needle. Using the narrowest hole presser foot and needleplate you have can help stop this, too.

Suggested reading for you:

http://www.schmetzneedles.com/pdf/ABC_Brochure.pdf

http://www.schmetzneedles.com/education.html

http://www.threadsmagazine.com/item/4993/sewing-lycra-blends

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