Patent ID: 7104941

Claim:
A tool pot comprising a tool attachment hole into which a tool is inserted and a tool gripping portion located in deeper side of the attachment hole, an inner surface of the attachment hole close to an opening end of the attachment hole being diverged toward the opening end and serving as a supporting surface for supporting a tool, wherein: the tool pot includes a cylindrical synthetic resin portion made from thermo-plastic resin and arranged over an entire length of the tool attachment hole from the opening end to the tool gripping portion; the synthetic resin portion includes an outer structure defining outer shape, an inner structure defining inner circumference of the tool attachment hole, a cavity provided between the outer structure and the inner structure, and joint ribs joining the outer structure and the inner structure; and each of the outer structure, the inner structure and the joint ribs has wall-thickness enough to secure rigidity of the synthetic resin portion and capable of suppressing mold shrinkage of the synthetic resin portion.