Special drill head fixture - permits head to rotate in mutually perpendicular planes and enables drilling normal to spherical surface

摘要

The drilling of holes normal to a spherical surface is facilitated by means of a special fixture. The fixture consists of a support clamped to a block which is in turn clamped to a machine tool. The support carries a plate which can be hinged about the pivot and locked by the adjusting screw. A swinging arm which carries the drill head can be swung in a plane perpendicular to the paper and locked by the screw which passes through a curved slot in the plate. The centre of curvature of this slot coincides with the point of the drill.