Reply To: Machining question…

[david pierce]

Tom,
The most accurate way to find the center of a round piece is to sweep it in with a dial indicator. The ball in the picture has some interupted areas however, you can still sweep in the quadrants. The clamping setup in the picture looks like it will not be stable enough to remain in one spot during the machining process. The V Block clamp is set back and the leverage will multiply the force against the clamp. Use the step blocks in your clamping set along with shim stock (cut up beer cans, aluminum foil, etc.) to hold the part from underneath. Add additional clamping as necessary to hold the ball in place during the drilling. If the brass rod through the hole is a tight fit you can sweep the top of the rod ends to make sure the rod is parallel with the mill bed. Another idea, if the rod is tight, would be to secure the rod in the hole with Loctite and clamp down on the rod to machine it. Once the hole is drilled the Loctite can be loosened with a torch and the rod removed.
david