It sounds very much as though you needed to renew the needle and to use the correct type of needle. You say that your fabric was a dense weave, that would have needed more effort to pierce and so the incorrect needle would likely have pushed the fabric down into the feed dogs. I would have tried on a spare bit of fabric and likely would have settled on a microtex needle
The bobbin thread could have had too much tension on it, there is a small screw on the casing which will release bobbin tension. The basic dynamics need to be understood. If tensions are equal for that fabric, then top and bottom threads will meet and link in the fabric
I have two berninas which can sew everything, a 380 and a vintage record 930. I also have a walking foot for both and only ever use schmetz or organ needles on any of my machines, which includes an overlocker and a cover stitch. I routinely clean and oil my machines and regularly change needles
skipped stitches are symptomatic of old or incorrect needles
Last three letters new game Novembet 13thr
Speculation: Who Will Be In Burnham's Cabinet?
Swimming pool was more like a talking pool!




