 Hose Sizes
Hose sizes are in terms of 1/16-inch increments. Aircraft hose dash size is not the I.D. of the hose. Dash size is the tube equivalent. For example, a -4 aluminum tube is 4/16 outside diameter. A -4 aircraft hose's inside diameter is
equivalent to the inside diameter of a -4 tube, usually 3/16 inch.
| Size | Hose I.D. | Tube Size |
|---|
| -4 | 3/16 | 1/4 |
| -5 | 1/4 | 5/16 |
| -6 | 5/16 | 3/8 |
| -8 | 13/32 | 1/2 |
| -10 | 1/2 | 5/8 |
Wrench size to hose dash size
An easy way of determining the hose diameter is to check the size of the wrench that fits on the hose nut ("B" nut)
Wrench size to hose size
| Hose dash size | wrench size - "B" nut |
|---|
| -3 | 1/2, 7/16, or 9/16 |
| -4 | 9/16 |
| -5 | 5/8 |
| -6 | 11/16 |
| -8 | 7/8 |
| -10 | 1 |
| -12 | 1-1/4 |
Careful - some fittings may use wrench sizes different than this chart. This chart shows the most common or typical wrench sizes.
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