dado joint in 18mm plywood

[WillumS]

Hi,
I'm making a corner shelf unit from 18mm ply, how deep should the dado joints be? I'm thinking of setting my router plunge depth to 8mm but not sure if this is too deep.

Is there a set rule, like a third, half, quarter or whatever of the material thickness?

 

[Burnerman]

I've always known these as housing joints, but make them not more than 1/2 way through....if the veneers of the ply determine the depth, choose the one that stops before halfway, rather than after.
John

 

[WillumS]

Thanks, it was 6 plies so I went for 6mm depth, through the first two layers. Seems to be holding up ok.

Makes sense to work to the layers in the wood itself.

Google told me it was a dado joint - maybe that's the american name for it.

 

[WillumS]

here's how they turned out - this is two of them, one on top of the other but they're wall mounted high level units in the kitchen.

View media item 70187

 

[Burnerman]

Looks like a good job - well done!
Dado is the american term, the european term is a trench.....housing for us!
John