Measure and use an acetylene torch to cut an 18-inch by 42-inch piece of 3/4-inch steel plate. Measure and cut two additional pieces of 3/4-inch steel, 12-by-18 inches.
Measure and cut two triangular pieces of 3/4-inch steel plate. These must be right triangles with two of the lines meeting at a 90-degree angle. Make the sides six inches and the hypotenuse 8 1/2 inches.
Lay the large piece of steel flat. Stand one of the 12-by-18-inch piece of steel on its long edge and touching the base of the flat-lying, 18-by-42-inch piece. Weld the two pieces of steel together with a stick welder. Stand the assembly up and weld the two triangular pieces of steel at the adjoining corners of the two large pieces of steel -- as connecting braces.
Measure and cut a 6-by-6-inch piece of 3/4-inch steel plate. Weld it flat onto the top, extended surface of the jack piston. Weld the base of the jack to the center of the 12-by-18-inch piece of steel on the inside of the angle connecting it to the 42-inch piece. (The jack will be standing between the triangular braces.)
Weld the other 12-by-18-inch piece of steel to the other end of the 42-inch piece of steel in an identical fashion as the other 12-by-18-inch piece. Invert the unit so that the jack is now upside down.
Measure and cut two 8-by-8-inch pieces of 3/4-inch steel. Cut an additional piece of 3/4-inch steel that measures 8-by-9 inches.
Weld the 8-by-9-inch piece of steel standing on the end plate with the 8-inch side up. Weld the 8-by-9-inch piece of steel in the center of the inside surface of the end plate. Weld the other two 8-by-8-inch plates on either side of the 8-by-9-inch plate, forming a 2 1/4-inch splitting surface. Do a build-up weld in the crevice on either side of the top edge of the 8-by-9-inch piece, forming a single splitting edge.