| 摘要 |
A method for manufacturing a vial for a level includes forming a blank body from molten material. The blank body includes an exterior surface and an internal bore. The exterior surface has an upper portion generally defining a portion of a cylinder, and a lower portion generally having a rectangular block shape. The internal bore has an interior surface that is substantially cylindrical so as to define a wall thickness that is substantially constant between the interior surface and the generally cylindrical upper portion of the exterior surface. The method also includes cooling the molten material that forms the blank body, and changing a shape of the formed cylindrical interior surface so that the wall thickness at a center portion of the blank body is thinner than the wall thickness at portions of the blank body located between the center portion and ends of the blank body.
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