I use a straight stitch plate too on my Pfaff 7570.

My Janome doesn't do it.

SDG which Janome is that? thanks for all your answers

My Brother will from time to time make a nest of thread, but i figured out wht it was Not enough material under the foot. my problem is i always turn the fabric before its finisg sewing

I try and remember to use a leader, or as one of the quilt people on tv called it, "Junk". Anyway, that works for me.

I've never had this problem with my old mechanical Bernina 1030.

the janome horizon has a button that closes the plate to a single whole

Use a small scrap of fabric to start sewing with, then it won't go down into the feed dogs. I do have to say my new Pfaff has never done this. It works beautifully.

I try to use a straight stitch plate and foot when I am piecing. It makes it much easier and less chance of getting "stuck"

My babylock espire never does, but the single hole throat plate is your best bet or leader fabric.