How do I determine the minimum outside diameter of a group of 7 wires of .150 OD that are arranged in a circle and touching each other around a center core.

I would think it would be 0.45

http://www.stetson.edu/~efriedma/cirincir/ccc7.gif

Proved as the smallest possible packing of 7 circles into a larger circle, by Graham in 1968.

If the interior circles have d=1 then total d = 3 (as can obviouslyt be seen)

It gets much more interesting above 7 :)

Erich's Packing Center (http://www.stetson.edu/~efriedma/packing.html)

Ridiculously interesting site.

Thanks for the help but I meant 7 wires in a circle around a central wire, so 8 wires in total

Jvc! Always better if you reply here! :)

If you had looked at the website I stated, it gives the answer:

http://www.stetson.edu/~efriedma/cirincir/ccc8.gif

d = 3.304*.15 = ~0.5 (0.4965)