I need a calculation to determine the outside diameter of a roll of film. UPDATE?

Question

I posted earlier but was confused. Thickness is .0024", roll footage is 2,400' and core diameter is 3". For the purpose of this question, the width is 14".

Thanks for your help.

Answer 1

What you have is a mid-core of 3 inch.

2400 ft = 28800 inches

circumference of inner core at moment = pi * 3 = 9.425 inches

Approximately-:
28800 / 9.425 = 3055.70 extra layers when film is wound onto inner.

In the real world the diameter gets bigger for every layer added (therefore the circumference increases accordingly)

1 layer = .0024 inches
3055.70 layers is 7.334 inches

Multiply this by 1.5-: 7.334 x 1.5 = 11.001 inches

Add original diameter (of inner) = 11.001 + 3 inches = 14.001 inches - which is near enough methinks.

Hope this is okay.

Answer 2

14 x 3.14 = 43.96
that's assuming the diameter of the whole roll is 14 inches (as I understood your question) if it's not, just multiply 3.14 (Pi) by whatever the diameter is.