Modified Stirling

This is a highly modified test-tube stirling
that was first located at an Internet site.
It was made by Steve McTighe who improved the design considerably.

The marbles have been replaced by steel ball bearings
(the marbles weren't round enough).
The unit has ball bearing pivots and leveling screws.
The diahpragm is contained within a cylinder
and works against a Delrin piston.

There is some real fine machining involved here.