Your tonsils are gland-like structures in the back of your throat. You have one located in a pocket on each side. Tonsils are made of tissue that contains lymphocytes -- cells in your body that prevent and fight infections.onsil stones, or tonsilloliths, are formed when this trapped debris hardens, or calcifies. This tends to happen most often in people who have chronic inflammation in their tonsils or repeated bouts of tonsillitis.
A self-centering chuck, also known as a scroll chuck, uses dogs (usually called jaws), interconnected via a scroll gear (scroll plate), to hold onto a tool or workpiece.
A self-leveling underlay is a cement-like product that can be pumped in liquid form onto the floor in order to create a level floor. Underlay is also the term for the material under roofing tiles; this roofing membrane is often made of rubber and is used to seal the roof and prevent leakage.