I bought this for an embroidery/sewing machine so I normally use it as a flat table. One problem I had was bumping the insert lever with my knee that dropped the insert to the lowered position while the sewing machine was partially sitting on the insert. Luckily it wasn't running at the time so I stopped it from tipping over. I ended up cutting the  horizontal end of the  insert "L" shaped lever off right at the bend and placing the black bumper on the cut end. It still functions but now I can't accidentally release the insert. Other than that it's a very nice addition to my other tables for my serger and heavy duty walking foot machine.