A size 90 TOP STITCHING needle was recommended at the Quilt/Sew Expo show demo.
Also - get that foot adjusted to the sweet spot. I'm not sure where that spot is yet, but it's usually just bearly above the fabric. I'm taking a ruler work class later next month - looking forward to learning all kinds of fun things!

Good Luck!
Donna Mc

I suggest winding a new bobbin. I had intermittent BAD tension that I could not diagnose... When my bobbin winder died and I bought a used one from a friend? Have not had a serious tension issue since.

I have the Janome 8900 and was having the same issue. I changed to a topstitch 90/14 needle and found that is working. I'm using Sew Fine 50 wt thread.

I think the foot is the problem. You said that you have quilted before with no problem. Only with this foot. Maybe readjusting the foot is the thing todo. If not set right, the fabric will lift slightly and cause the thread to not slip through the fabric and cause shredding. I know on my long arm I have to have the foot set correctly to get a good stitch and no thread breakage.

Change thread. Use 90/14 topstitch needle. Make sure your foot lever is down...and ruler foot closer to your fabric. Thread is in the take up lever,can't tell you how often this happens). Sometimes a microtex needle 90/14 is the answer. I took a free motion boot camp class and was told to bring a microtex needle 90/14. My thread shredded, broke a needle, pulling loops to the top of the fabric.....brand new Janome 8900. I took this machine out of the box, with the factory needle in it, don't know the size, set it up for free motion, worked perfectly. Next day we were off to the boot camp. But I did one thing different. I bought some beautiful thread, never, opened. Finally the instructor came over, person who told me to use the Microtex needle, she tried, same shredding. I took the thread off the machine and happened to turn the small cone upside down and inside the tube it said what size needle to use with that thread. Bought the needle at the quilt shop where the boot camp was being held....thank goodness they had one...and away I went. No problems for the rest of the class. Lessoned learned, match your needle to your thread.
BTW I love my Janome 6600. It is a workhorse of a machine. The 8900 is wonderful too. Best wishes for solving this mystery.Oh, and be careful with the shredding, it can lead to the dreaded broken needle that flies into your face. Ask me how I know.

Thank you all for your suggestions. I took my machine in for servicing, and while it's behaving a little better, I am still getting the intermittent skipped stitches and broken threads, even after switching to a 90/14 top stitch needle, rewinding bobbins, trying different thread... The ruler work is going a little better, but I'm still searching for the sweet spot with the foot... I tried quilting a table runner, and found a couple of places where the seams weren't nested properly, and the foot wouldn't even go over them... need to adjust it up a bit...
I wish I had purchased the convertible foot and ruler foot, but the 3 dealers I called weren't knowledgeable enough to recommend it. That frustrates me a little. I'm off to do more practicing.. and troubleshooting...

Hi, I am new to this board but came here because I have had the same problems as Kris P except my machine is a Janome 9400 QCP. I just had it in for a "spa day" and took it back a couple of days ago because of the thread shredding, skipped stitches and all with the Westalee ruler foot. I was told in no uncertain terms it is not my machine though they replaced the bobbin case in the "spa day" and it seems loose to me. Anyway, I was reading online today all the things that have been suggested here about making adjustments but the ruler foot not being close enough to the material caught my eye. Also the advice about working with batiks. (They are more difficult because they have a tighter weave. I got out the free motion foot that came with the machine that I have used on a few quilts recently, not the hopper foot but the closed toe one and made a quilt sandwich with the batik I am using as a backing and the same cotton filler. I applied the 505 adhesive as I did with the quilt and tried it again. It is working fine. I have an Angela Walters ruler and used it. It working fine now. I think it is the Westalee ruler foot, that it does not keep the sandwich from pulling up from the stitch bed. Does this sound right to anyone? Has anyone had this same problem? I know Janome has come out with an up date which includes 4 new feet and a usb adjustment to the machine which causes the computer to recognize the feet. One of the feet is a ruler foot. It is $119.00 and Sewing Machines Plus in So Cal has the kit. I didn't buy it because I don't see a need for the other feet and I had already purchased what I have.

I am having the same problem with the Janome 9400QCP. I use Janome needles which the machine seems to perfer. It still misses stitches in free motion quilting but not regular sewing. I was assured it is not the machine so I did went back to the free motion foot closed toe and it seems to be working now.

I was having skipped stitches with size 50 cotton thread. But what an amazing difference Metler Poly-sheen, size 40, made! I really want to order a whole bunch of it and share it with my friends!

I posted on the 22nd about using the closed toe quilting foot that came with the machine. I worked with it more and it started skipping stitches here and there then a few here and there mostly when I back up (pull the quilt toward me. It got bad so I called around and found the upgrade with the four new feet in them including the ruler foot and installed that. The whole process works much better. For one with a real ruler foot I don't have to move the quilt so much with saves time and muscle. It is only skipping one or two stitches once in a while pulling the quilt toward me. I did change to the single hole bed plate from the zig zag one because I was told it would help the needle keep in place. I think this machine might be one that you have to stick with the Janome products. Sigh. I am much happier with how it is working though.