Also if its stainless steel on stainless steel you could be encountering galling, that's when the metal binds with a similar metal and bonds itself together. Stainless is notorious for galling, not a great metal IMO there are better for almost every condition, but highly corrosive situations.
As Teo_ audio mentioned a little lubricant can help.
Glen
As Teo_ audio mentioned a little lubricant can help.
Glen