drilling tool for the development of evidements in masonry concrete building components, or other fragile materials

摘要

The milling tool is used to make under-reamed openings in building components of masonry or other brittle material. It comprises a driven shaft together with an arrised annular cutting head, the latter being mounted free to rotate on a trunnion which is offset from the shaft. The transverse internal section of the milling head's body may exceed the transverse section of the trunnion, the envelope of the latter oversailing the former at one or more locations, and the former comprising an oval, a circular, or a polygonal opening.