If your table legs can get bumped sometimes they need to be put back in the correct position just being a little off will cause vibrations. The legs on a folding table may need to be pushed gently out away from the table for more stability. The bigger machines need a very good table or something sturdy because of there weight and the computer components shouldn't be shaking when trying to sew or embroider.

Good Luck

Suzy

I cut up a Yoga mat and place a piece of it under all my machines including my serger. I bought the yoga mat a a thrift store so it is very inexpencive...

a towel will work just fine

I have an older, less expensive machine, that does the 'watusi' when I sew with it, so I just put a mouse pad under each end. No more 'dancin'. You could try stacking two under each end if you need more pad.

I was using an old metal desk that was extremely heavy to sew on. Never had a problem. When we remodeling my sewing room, I switched the old desk for a newer one with a huge top. The newer desk had been used by a drafting firm and I thought it would be wonderful to have so much space. Now my table top seems to be "jumping". Disappointing but I'm not saying a word to my hubby or the crew it took to bring it into the house.

First thing is tighten any screws on your table. That usually is the kicker.
Secondis the really inexpensive web like rubbery mat that is cut up for place mats shelf liners and nonslip rug pads works great.

I have an shower mat under mine. It is the foamy one with suction cups on the back. Seems to work good. Had trouble with my machine moving to the back of table when fmq as it is kind of slippery. It is one of those poly folding tables that I got at Costco.

Try putting some banding around the harp area and velcro it to a board or padding underneath. Perhjaps try using a smaller, steadier table.

They sell this rubberized material for shelves. I have that under my machine it work and you can cut to the size you want.

I use the liner that comes in colors. Its like a rubber and holds everything. I put it under my bread boards also.