'METHOD OF DRILLING OF HEMISPHERICAL WORK PIECES HAVING LARGE DIAMETER AND HIGH THICKNESS BY PLACING THE WORK PIECE IN A HOLDING DEVICE'

摘要

The invention relates to a method of drilling holes in a hemispherical work piece having high thickness, comprising placing the work piece in an inclined position on an inclined circular plate (07) ; clamping the work piece with fasteners (08, 09) so that the displacement of the work piece in any of the three planes (XYZ) is arrested; positioning the work piece to the required angle by a plurality of triangle fabricated frames (12) which is placed in between a third plate and a second plate (06, 02) on the vertical direction between the third plate and a first plate (06, 01) in the horizontal direction; and drilling a first hole in the vertical boring machine and drilling a second hole in a horizontal boring machine without further measurement of the first hole-dimension.