a temperature rise of approximately 1 u00b0 f per minute to 600 u00b0 f and left at this temperature for about 1 hour thereafter the temperature is again increased at 1 u00b0 f per minute to 700 u00b0 f which temperature was maintained for 4 hours thereafter cooling is begun at a rate of approximately 2 u00b0 f per minute and upon cooling to room temperature the block is ready to machine as described the block thus formed may be ground in any precision lathe generally used to grind fasteners however when the fibers and resins described herein are employed a fine grinding wheel is desirable and a carbide or diamond grinding wheel with a grit of 100 to 120 is preferred a typical grinding speed is about 3000 revolutions per minute with a 11 2 inch diameter wheel speed of rotation and travel of the lathe should be relatively slow to keep the grinding pressure low it will be appreciated that the fine particles and dust created during such grinding should be collected with a vacuum system fig1 shows the three dimnsional arrangement of the fibers in the woven preform of the preferred embodiment although it should be understood that other types of multi dimensional weaves may be employed as required by specific applications in that figure a woven preform 10 is shown as comprising a plurality of fibers 12 disposed along an x axis a second plurality of fibers 14 disposed along a y axis and a third plurality of fibers 16 along a z axis each of the pluralities 12 14 and 16 are seen to be disposed at angles of 90 u00b0 the center to center spacing of the fibers of.