What the thread found

• Placing the gimbal in a refrigerator allows the threaded sections to contract slightly, creating play that can help loosen a stuck cover.
• Gentle heating with a heat gun (minimal temperature) can also ease removal by inducing slight expansion.
• Securing the gimbal body to a post and clamping it provides stability when turning the upper inner ring during removal.
• Turning at the location where the gimbal is normally hand-operated and opening from below improves mechanical advantage.
• If standard methods fail, fabricating a custom removal tool with increased lever length can provide sufficient torque.