Set the bottle jack on a flat surface and sand off the paint halfway down the middle. This is where the steel sleeve weld will be.
Set the welder up according to the manufacturers directions.
Put on the goggles and gloves. Slide the steel sleeve over the top of the bottle jack until the bottom edge is over the sanded area. Weld the steel sleeve in several spots to hold it in place.
Weld the sleeve to the jack all the way around the circumference. Allow the metal to cool.
Position the bottle jack on the flat surface with the pump handle facing to your right. Drill a hole in the side of the sleeve that is centered and is 2 inches in from the top rim. Drill another hole directly opposite in the sleeve.
Cut the square aluminum tubing with holes into four, 24-inch lengths, using the ruler and the metal saw.
Place a self-locking washer on a bolt and set it aside. Place the end of a 24-inch aluminum tube against one of the holes you just drilled. Align the holes. Insert the bolt with the washer from the outside through the aluminum and steel sleeve. Place a self-locking nut on the bolt on the inside of the steel sleeve. Attach another 24-inch aluminum tubing to the opposite hole in the steel sleeve in the same manner.
Place the two remaining 24-inch aluminum tubes flush against each other on a flat surface, lengthwise with the ends aligned. Bolt them together.
Attach locking caster wheels to one end of the two abutted aluminum tubes along a 4-inch side.
Turn the bottle jack with the attached aluminum tubes upside down with the pump handle facing to your left.
Place the two joined aluminum tubes in between the aluminum tubes attached to the bottle jack sleeve. Do this by inserting the wheeled end underneath the bottle jack -- wheels down -- from the right and out behind the bottle jack. Insert a bolt with a nylon washer through the four aluminum tubes at the midpoint on the long sides. Place a nylon washer and self-locking nut on the end of the bolt and tighten.