On Wed, 26 Aug 2020 16:02:35 -0700 (PDT), pmailkeey
wrote:

On Sunday, 4 January 2004 at 22:39:09 UTC, Leo Lichtman wrote:
Cliff Knight wrote: Correct, "swing" in machine tool talk is radius (like
a swing hanging from a tree.(CLIP)
^^^^^^^^^^^
Cliff, too bad you didn't stop right after the word "correct." Pal had it
right, so "correct" is correct. But swing is not a radius. The radius of
the maximum size his lathe will turn is 3"--the swing is 6", the DIAMETER.
The illustration of a swing hanging from a tree merely adds to the error of
calling the radius the swing.

'Swing' is the radius, not diameter. Think of how long a pendulum would be swinging from the spindle. Same wrt crank length on a crankshaft.

In the US, swing of a lathe is the diameter of the largest workpiece.
I gather that in at least parts of Europe, the swing is the maximum
radius, half the diameter. I don't know which definition is used in
the UK.

Joe Gwinn