First, Maxilock is serger thread and is the cheapest, spun poly thread on the market. I would suggest a different thread. Serger thread is different than cone thread, and Maxilock is made for sergers. There are many, quality threads on the market that are sold on cones that are not serger threads. Second, it sure sounds like a timing issue if you can get it to stitch with a large needle and get skipped stitches with smaller needles. You should investigate this further and if you don't feel you're up to servicing it you should take it to a local repair shop. There are quite a few sites if you google that show the basics of timing or making sure your machine is in time. I have no idea what needle this model takes, but that could be your whole problem-or the timing. An incorrect needle will not give you good results. 70 wt thread is VERY fine and I've never heard of anyone quilting with it as it's not a very strong thread. I guess if one was doing some serious micro quilting to reduce bulk...but it wouldn't be my choice for quilting. It's mainly a bobbin thread for embroidery or heirloom type thread, I believe. Just like serger thread is usually 5 threads to wrap around a seam and build strength. Personally and there have been many topics about this, I wouldn't use it for quilting or piecing.
I would recommend you go to Superior Threads and read what they have to say about the different threads and thread weights. Good luck.
Last edited by Candace; 03-27-2013 at 08:28 PM.