I used
this tutorial to make them. She suggests a pair of hinges in the bottom of the pincushion to keep it weighted on the table, and then I stuffed it with toy stuffing (can't remember the proper name for it right now!). I only used one hinge in mine, and wish now that I'd used two, but it does stay on the table (just seems a little precarious!). I wrapped the hinge in a plastic sandwich bag, and sellotaped it so it stayed around it nice and tight, because I used an old hinge from my Dad's garage, and didn't want any issues with rust! The only issue I had with the tutorial was when I was trying to sew in the "boning" at the top of the thread catcher...my stitching was so bad on the one I had chosen to be my friend's one (the one with the better piecing) that I had to swap, and give her the other one!