Abstract: Apparatus for supplying coolant to the location of contact between a workpiece and a grinding wheel in a grinding machine has one or more reciprocable and indexible carriers each of which removably or fixedly supports two or more different nozzles. This enables each carrier to maintain a selected nozzle in an optimum position for delivery of one or more streams of coolant to the location of contact. At the same time, the other nozzle or nozzles are sealed from a source of coolant so that the coolant is not wasted when a particular nozzle on the carrier is in the process of delivering an optimal quantity of coolant against a workpiece. The nozzles can be removed from their carrier or carriers individually or in groups of two or more. Alternatively, each carrier with all of the nozzles thereon can be replaced with a carrier mounting a different set of nozzles.

Abstract: A double head grinding machine for the roots of turbine blades or similar complex workpieces with concave and/or convex surfaces has two parallel horizontal spindles the upper of which carries a single grinding wheel and the lower of which carries two coaxial grinding wheels. The base of the machine frame supports a table which is movable by a first motor in a direction at right angles to the axes of the spindles, tangentially of the grinding wheels and along a horizontal path below the spindles. A work holder on the table is movable by a second motor along a sloping path in a direction making an angle of 30 degrees with the axes of the spindles and at right angles to the direction of movement of the table in such a way that the workpiece which is held in the holder can be moved toward or away from the grinding wheels.