Convert AWG to Inches AWG (American Wire Gauge) is a common way of specifying wire sizes. Your task in this challenge is to convert from a given gauge to the diameter of the wire in inches.

The size in inches for the gauges from 4/0 to 40 are shown in the table below:

Gauge to inches table

| AWG | Diameter (Inches) |
|-----|-------------------|
| 4/0 | 0.46              |
| 3/0 | 0.4096            |
| 2/0 | 0.3648            |
| 1/0 | 0.3249            |
| 1   | 0.2893            |
| 2   | 0.2576            |
| 3   | 0.2294            |
| 4   | 0.2043            |
| 5   | 0.1819            |
| 6   | 0.162             |
| 7   | 0.1443            |
| 8   | 0.1285            |
| 9   | 0.1144            |
| 10  | 0.1019            |
| 11  | 0.0907            |
| 12  | 0.0808            |
| 13  | 0.072             |
| 14  | 0.0641            |
| 15  | 0.0571            |
| 16  | 0.0508            |
| 17  | 0.0453            |
| 18  | 0.0403            |
| 19  | 0.0359            |
| 20  | 0.032             |
| 21  | 0.0285            |
| 22  | 0.0253            |
| 23  | 0.0226            |
| 24  | 0.0201            |
| 25  | 0.0179            |
| 26  | 0.0159            |
| 27  | 0.0142            |
| 28  | 0.0126            |
| 29  | 0.0113            |
| 30  | 0.01              |
| 31  | 0.00893           |
| 32  | 0.00795           |
| 33  | 0.00708           |
| 34  | 0.0063            |
| 35  | 0.00561           |
| 36  | 0.005             |
| 37  | 0.00445           |
| 38  | 0.00397           |
| 39  | 0.00353           |
| 40  | 0.00314           |


Clarifications


For gauges less than 0, you can take the input as either 3/0 or 000
You only have to support from the given 4/0 to 40
The Wikipedia page has some helpful formulas you can try to use if you don't want to hardcode everything
Output your answers to at least 3 sig-figs
This code-golf, so shortest code in bytes wins!
J, 33 26 bytes

0.46%92^39%~*@".{3+".,~1-#


Try it online!

Takes input as a string with gauges less than zero as a string of zeroes. Finds the index of that string and divides 0.46 (the diameter of 0000) by the 39th root of 92 (the ratio between gauges) that many times.

Explanation

0.46%92^39%~*@".{3+".,~1-#  Input: string S
                         #  Length of S
                       1-   Subtract it from 1
                   ".,~     Eval S and append it, forms [1-len(S), eval(S)]
                 3+         Add 3 to each
            *@".            Sign of the eval
                {           Use that to index into the previous list
        39%~                Divide by 39
     92^                    Raise 92 to that power
0.46%                       Divide 0.46 by that and return