Lapidary sphere grinder

A sphere grinding machine, comprising, in combination, a table supported upon legs, a motor driven grindstone carried upon said table providing a means for grinding a surface of a stone for imparting a spherical shape thereto, a slide member with an insert-carrying stone holder carried by said table with crank means for moving said stone holder towards and away from said grinding wheel, an angularly positioned and shaft mounted rubber tired wheel carried on plate means above said table for intermittently rotating said stone being ground, pulley, belt, and motor means carried upon said plate, providing rotation means for said rubber tired wheel, crank means for moving said plate carrying said rubber tired wheel, a chute carried by said table providing gravity takeoff means for the ground away material of said stone, switch means on said table for controlling said motor driven grindstone and a coolant recirculating pump, said stone holder being rimed, and secured fixedly, to said slide member which holds said stone holder, and said stone holder receives a removable insert having an opening which aligns with an opening of said stone holder, said stone being presented and retained within said opening of said stone holder, against a peripheral edge of said grindstone, said crank means for moving said stone holder enabling said insert to be brought away from said grindstone as wished, said rubber tired wheel having an annular groove around its outer periphery forming a two-contact point surface against which said stone rolls, said wheel being secured to a shaft mounted to said plate means which is crank operated, so as to move said rubber tired wheel to and away from said stone being ground, said rubber tired wheel being secured fixedly to said shaft by a suitable nut fastener, said shaft being supported within block means secured fixedly to said table and said rubber tired wheel including a semicircular notch at one point on an outer periphery of said rubber tire, said notch when rotated into position for communication with said stone enabling said stone to be momentarily released and reset itself in another position against said rubber tired wheel resulting in an irregularly shaped stone being spherically ground.