Fermentor grommet hole size

[Corvato]

I keep going out shopping, and think i want to get some hose that will fit tightly into the grommet that i usually have my airlock in. I know the hole the grommet is in is 1/2", but don't know what the interior hole size to the grommet is... I keep forgetting to measure.

what exteriror dimension of hose will fit this grommet tightly?

 

[HairyDogBrewing]

The grommet is size 3/8" x 1/2".

 

[Funkenjaeger]

5/16"IDx7/16"OD vinyl tubing (probably the most commonly used size for siphon tubing) fits in standard airlock grommets (or stoppers, carboy caps, etc) quite well.

 

[Corvato]

OK, both of these can't be true... if the inside of the grommet is 3/8"... how can a 7/16" cable go into it?... isn't the 7/16" cable 1/16" wider than the hole you are running it through?

 

[HairyDogBrewing]

I use 3/8 OD copper tubing and it fits the grommet well.
Since rubber and vinyl are both flexible, 7/16 tubing might fit into a 3/8 rubber grommet
with some difficulty.