Revolving tool holder for a rotary machine such as a lathe or drill

A turret for a turning machine, comprising:

• a base member arranged rotatably on the cross-slide rest and rotatable relative thereto about a first rotational axis,
• a turret head arranged rotatably on the base member, said turret head being rotatable about a second axis of rotation which defines an offset angle with the first axis of rotation, said turret-head having
• a first ring of tools the shank axes of which lies on the surface of an imaginary cone, with the vertex of the cone lying on the second axis of rotation and with half the vertex angle of the cone plus the offset angle forming a right angle, and
• a second ring of tools, the shank axes of which lie on the surface of a second imaginary cone the inclination of which is directed towards the vertex of the cone of said first ring and the axis of both said cones being identical and lying on said second axis of rotation, both said cones having identical vertex angles.

A turret for a rotary turning machine having a cross-slide, comprising:

• a base mountable on said cross-slide for rotary movement about a first axis,
• a turret head arranged on said base for pivotal movement relative to the base about a second axis inclined at an angle .alpha. to said first axis,
• a first annular array of tool holders provided on said turret head and arranged whereby, when tools are mounted in said holders, the axes of the tools are located on the surface of an imaginary cone having its vertex located on said second axis, and the arrangement of the turret head being such that .alpha. + .beta. = 90.degree. where 2.beta. is the angle defined at the vertex of the cone, and
• a second annular array of tool holders provided on said turret head and arranged whereby, when tools are mounted in said holders, the axes of the tools are located on the surface of a further imaginary cone having its vertex directed towards the vertex of said first mentioned cone and also located on said second axis, said further cone having a vertex angle which is equal to the vertex angle of said first mentioned cone.