My 66 is not particular when it comes to needles at all, any of the regular brands stitch perfectly, even low priced Chinese made needles stitch fine. Some brands are finer made though, and a bad batch of needles can happen. What sorted out my machine was cleaning the feed dog area and under the bobbin case. After cleaning it's all about tending to the oil points and starting to use the machine. This model gives perfect even stitches on any fabric when sorted out. Make sure you match needle and thread size correctly, it makes all the difference.