# Box joints



## lbtrail (Dec 23, 2014)

I want to build drawers using box joints. My question is can I cut 1/2 & 3/4 stock at the same time like you would do making dovetails.
Thank you


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## bobro (Oct 24, 2014)

If you stand a 3/4 thick board on end and run it over a dado blade or router bit 1/2 up from the table, a 1/2 thick board run over the same blade or bit will fit in to the 3/4 thick board at a right angle as far as the depth of the cut, but it will fall short 1/4 as far as the thickness of the 3/4 board.

So, no. BUT if you cut all your fingers at the depth of the thickest boards, 3/4 in this case, then you can trim the resulting overhanging 1/4 off the thicker board after joining. You just have to make the thicker boards 1/2 (that is, 1/4 + 1/4) longer than the final dimension.


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## ADHDan (Aug 17, 2012)

Not that bobro has it wrong, but (maybe) to restate it more simply: in a box joint, the fingers need to be at least as long as the thickness of the board they mate with. So, if you cut all of your fingers based on the thickness of your thickest board you will be fine.


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## waho6o9 (May 6, 2011)

HTH


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## lbtrail (Dec 23, 2014)

Thank you all for your info. It helped a lot


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## bobro (Oct 24, 2014)

> Not that bobro has it wrong, but (maybe) to restate it more simply: in a box joint, the fingers need to be at least as long as the thickness of the board they mate with. So, if you cut all of your fingers based on the thickness of your thickest board you will be fine.
> 
> - ADHDan


Yes- if you gang the boards, which is a good idea for speed and accuracy, you have to go to the depth of thickest board, which means you're going to have some overhang to trim off, and you have to compensate beforehand for that, when cutting the boards to length.

By the way, I learned this the hard way when I was a teenager 30 years ago. "Face-palm". My dad taught me all kinds of basics but then let me make my own mistakes, in order to learn how to think ahead and not just work by rote.

Oh- when you are running the ganged boards over the blade or bit, it's a good idea to back the stack with a sacrificial board, because it's possible to get blowout on the edges of the fingers of the last board.

Let's see…yip, on the mass-produced finger-jointed box my wife got there's a blowout exactly like I did on my first finger joints.


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