What is "mandrels"

Usage examples of "mandrels".

At first my efforts were clumsy, lopsided blobs that clung perversely to the mandrels, the fine metal rods that kept a hole in the middle.

But he sees tongs shaped almost like serpents, and there are two large cone mandrels on huge weighted bases.

The teeth were very deep, and the clay was built up around turned brass mandrels to assure concentric bearings.