I have several Janome machines from a 4120, S9, 15000 and my new M7 and I’ve been with Janome for over 35 years - way before they had the built in Acufeed/Acuflex systems. For sewing those pillow cases, I’ve sewn many and did them on various machines and never had the problem you seem to be having. I used my regular “A” foot that usually comes on the machine out of the box. I didn’t break any needles and probably was using a Schmetz 12 or Janome 11 again the ordinary needles for most sewing. What I did when I got to those thicker places in the seam, was to slow down, and keep hold of the fabric on the back and front - I didn’t pull, just guided the fabric through. If on occasion the machine didn’t move, I would lift the foot (this was before I knew “how” to use the little button on the side of the A foot) and gently guide the fabric up under the needle. A pain the backside to be sure, but it worked and I got my seam sewn. I want to say that even my little 4120 and previous to this my Jam Platinum 760 would sew through a pillowcase french seam at the cuff with a flange added to the cuff with no problems. Just keep trying - you’ll get your machine to work for you and then you’ll love it.
Now you are going to ask, “How could you have had a Janome with that little button feature for 35 years and NOT know how to use it. Well, long story short, I lived in Northern Saskatchewan 150 miles from the nearest city and it wasn’t a big place, but my dealer was there. we only went into the city about a dozen times a year and some of those were after business hours to visit our parents, who lived further away. Our trip was 150 miles with NO towns and 100 of those was forest with just the road going through.
Back to the problem. What kind of needles are you using, Your 14000 should handle what you are sewing - after all it is quilting cotton, right, and usually that isn’t a difficult fabric to deal with. If you watch the video link that Jim sent and follow those guide lines your problems should be solved.
Now to the M7 machine. At one dealers, I decided to try the demo machine and put 12 layers of denim under the needle - that was not a good idea as the needle broke, the machine sang a nasty little tune and jammed. I was very embarrassed, because we had been told that it would sew 9 layers without a problem, but I HAD to push the envelope. I did confess to the dealer and her technician what had happened so that the machine could be checked for burrs in the needle plate and the timing. I know that it still worked, but I wasn’t going to be a bad person who did something that might have caused a problem down the road, when this machine left the store at a demo sell off. I would attempt those layers again, but I think I would “hand walk” the needle through the few stitches that needed to be made in an actual seam situation. We are after all using a sewing machine with a fine needle, even if it is a size 20 - it isn’t a drill we’re operating. I love my M7 and think it will do everything and more than I would ever expect to make on a sewing machine. The lighting is phenomenal and I think that’s almost the most important thing for any of us that are in our “better years” and still have some vision.
Cheryl - Saskatoon