"Matty F" wrote in message
...
OK I've decided to use billiard balls for my Newton's cradle.
But I would rather not drill into the balls or try to glue things on
them.
How can I hold the balls in position?
This very large version has some rings, which is what I am
considering:
http://i48.tinypic.com/1euurq.jpg


One approach could be to grind a flat on the top of each ball. Manufacture a
plane disk whose diameter matches the flat. A metal disk would enable you
to solder or braze or machine two pickup points at the edges of the disk,
diametrically opposite one another.

DDS