Mold for forming resinous domed article and method of producing same

A method of producing a male block of a resinous dome-forming mold, the male block having a dome-shaped protrusion which includes a hemispherical section that is just half a sphere and a cylindrical section continuing from an end of the hemispherical section, comprising the steps of:

• preparing a spherical block having a spherical surface ranging over at least more than half a sphere;
• rotating said spherical block around an axis passing through the center of said spherical block;
• grinding an area of the spherical surface of said spherical block ranging over more than 180° from a top of the spherical surface through which the axis of rotation passes to a circumference thereof using a grindstone with a curved surface having substantially the same radius of curvature as that of the hemispherical section of the male block;
• cutting off a grounded portion of said spherical block to complete the hemispherical section of the male block;
• preparing a block on which the cylindrical section of the male block is formed;
• and
• joining the cylindrical section to the hemispherical section to complete the male block.