Ball valves are used to control the flow of liquids, steam, chemicals and foods. They are simple, inexpensive and reliable valves that are often seen in laboratories, factories and food processing. They consist of a ball that can be rotated — usually through 90 degrees. A hole drilled through the ball, allows fluid flow when the hole in the ball is aligned with the flow. When the ball is rotated, the ball blocks the flow.


1. Clamp the ball in a vice and drill a hole through the ball. A ball with a single hole drilled all the way through it will make a ball valve that switches a single stream on and off. For a more complex valve, turn the ball and drill another hole from the surface of the ball to intersect the first hole. The balls with two holes are used where three lines come together. These ball valves can close off any one, or all three paths.


2. Attach a rod to the ball so the rod is perpendicular to the hole that goes through the ball. If you are using a plastic ball, the rod should be plastic and should be attached with crazy glue. If the ball is metal, the rod should be metal and should be welded. In either case, the joint should be polished smooth so the ball valve will move easily. The rod should terminate in simple metal handle. The handle should be attached in such a way that the handle lines up with the flow through the gate.


3. Install the ball valve. In the simplest cases this could be a simple as punching a small hole and inserting the ball and rod into a plastic tube. If this is the case, the handle should be attached only after the ball and rod are in place.


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